@book{JanserHavermann2012, author = {Janser, Frank and Havermann, Marc}, title = {Inkompressible Str{\"o}mungen}, publisher = {Mainz}, address = {Aachen}, isbn = {978-3-86130-446-3}, pages = {189 S. : Ill., graph. Darst.}, year = {2012}, language = {en} } @inproceedings{JeanPierrePBaqueBillietal.2018, author = {Jean-Pierre P., de Vera and Baque, Mickael and Billi, Daniela and B{\"o}ttger, Ute and Bulat, Sergey and Czupalla, Markus and Dachwald, Bernd and de la Torre, Rosa and Elsaesser, Andreas and Foucher, Fr{\´e}d{\´e}ric and Korsitzky, Hartmut and Kozyrovska, Natalia and L{\"a}ufer, Andreas and Moeller, Ralf and Olsson-Francis, Karen and Onofri, Silvano and Sommer, Stefan and Wagner, Dirk and Westall, Frances}, title = {The search for life on Mars and in the Solar System - strategies, logistics and infrastructures}, series = {69th International Astronautical Congress (IAC)}, booktitle = {69th International Astronautical Congress (IAC)}, pages = {1 -- 8}, year = {2018}, abstract = {The question "Are we alone in the Universe?" is perhaps the most fundamental one that affects mankind. How can we address the search for life in our Solar System? Mars, Enceladus and Europa are the focus of the search for life outside the terrestrial biosphere. While it is more likely to find remnants of life (fossils of extinct life) on Mars because of its past short time window of the surface habitability, it is probably more likely to find traces of extant life on the icy moons and ocean worlds of Jupiter and Saturn. Nevertheless, even on Mars there could still be a chance to find extant life in niches near to the surface or in just discovered subglacial lakes beneath the South Pole ice cap. Here, the different approaches for the detection of traces of life in the form of biosignatures including pre-biotic molecules will be presented. We will outline the required infrastructure for this enterprise and give examples of future mission concepts to investigate the presence of life on other planets and moons. Finally, we will provide suggestions on methods, techniques, operations and strategies for preparation and realization of future life detection missions.}, language = {en} } @inproceedings{KapoorBollerGiljohannetal.2010, author = {Kapoor, Hrshi and Boller, Christian and Giljohann, Sebastian and Braun, Carsten}, title = {Strategies for structural health monitoring implementation potential assessment in aircraft operational life extension considerations}, series = {2nd International Symposium on NDT in Aerospace : November 22-24, 2010 Hamburg, Germany}, booktitle = {2nd International Symposium on NDT in Aerospace : November 22-24, 2010 Hamburg, Germany}, publisher = {Dt. Gesellschaft f{\"u}r Zerst{\"o}rungsfreie Pr{\"u}fung}, address = {Berlin}, organization = {Deutsche Gesellschaft f{\"u}r Zerst{\"o}rungsfreie Pr{\"u}fung}, isbn = {978-3-940283-28-3}, pages = {9}, year = {2010}, language = {en} } @inproceedings{KapoorBraunBoller2010, author = {Kapoor, Hrshi and Braun, Carsten and Boller, Christian}, title = {Modelling and optimisation of maintenance intervals to realize structural health monitoring applications on aircraft}, series = {Structural health monitoring 2010 : proceedings of the Fifth European Workshop on Structural Health Monitoring held at Sorrento, Naples, Italy, June 28 - July 4, 2010 ; [EWSHM]}, booktitle = {Structural health monitoring 2010 : proceedings of the Fifth European Workshop on Structural Health Monitoring held at Sorrento, Naples, Italy, June 28 - July 4, 2010 ; [EWSHM]}, editor = {Casciati, Fabio}, publisher = {DEStech Publ.}, address = {Lancaster, Pa.}, isbn = {978-1-60595-024-2}, pages = {55 -- 63}, year = {2010}, language = {en} } @misc{KeimerGirbigMayntzetal.2022, author = {Keimer, Jona and Girbig, Leo and Mayntz, Joscha and Tegtmeyer, Philipp and Wendland, Frederik and Dahman, Peter and Fisher, Alex and Dorrington, Graham}, title = {Flight mission optimization for eco-efficiency in consideration of electric regeneration and atmospheric conditions}, series = {AIAA AVIATION 2022 Forum}, journal = {AIAA AVIATION 2022 Forum}, publisher = {AIAA}, address = {Reston, Va.}, doi = {10.2514/6.2022-4118}, year = {2022}, abstract = {The development and operation of hybrid or purely electrically powered aircraft in regional air mobility is a significant challenge for the entire aviation sector. This technology is expected to lead to substantial advances in flight performance, energy efficiency, reliability, safety, noise reduction, and exhaust emissions. Nevertheless, any consumed energy results in heat or carbon dioxide emissions and limited electric energy storage capabilities suppress commercial use. Therefore, the significant challenges to achieving eco-efficient aviation are increased aircraft efficiency, the development of new energy storage technologies, and the optimization of flight operations. Two major approaches for higher eco-efficiency are identified: The first one, is to take horizontal and vertical atmospheric motion phenomena into account. Where, in particular, atmospheric waves hold exciting potential. The second one is the use of the regeneration ability of electric aircraft. The fusion of both strategies is expected to improve efficiency. The objective is to reduce energy consumption during flight while not neglecting commercial usability and convenient flight characteristics. Therefore, an optimized control problem based on a general aviation class aircraft has to be developed and validated by flight experiments. The formulated approach enables a development of detailed knowledge of the potential and limitations of optimizing flight missions, considering the capability of regeneration and atmospheric influences to increase efficiency and range.}, language = {en} } @phdthesis{Keinz2018, author = {Keinz, Jan}, title = {Optimization of a Dry Low NOx Micromix Combustor for an Industrial Gas Turbine Using Hydrogen-Rich Syngas Fuel}, publisher = {Universit{\´e} Libre de Bruxelles - Brussels School of Engineering Aero-Thermo-Mechanics}, address = {Br{\"u}ssel}, year = {2018}, language = {en} } @inproceedings{KemperHellenbroichEsch2009, author = {Kemper, Hans and Hellenbroich, Gereon and Esch, Thomas}, title = {Concept of an innovative passenger-car hybrid drive for European driving conditions}, series = {Hybrid vehicles and energy management : 6th symposium ; 18th and 19th February 2009, Stadthalle Braunschweig}, booktitle = {Hybrid vehicles and energy management : 6th symposium ; 18th and 19th February 2009, Stadthalle Braunschweig}, publisher = {Gesamtzentrum f{\"u}r Verkehr (GZVB)}, address = {Braunschweig}, isbn = {978-3-937655-20-8}, pages = {264 -- 287}, year = {2009}, abstract = {The downsizing of spark ignition engines in conjunction with turbocharging is considered to be a promising method for reducing CO₂ emissions. Using this concept, FEV has developed a new, highly efficient drivetrain to demonstrate fuel consumption reduction and drivability in a vehicle based on the Ford Focus ST. The newly designed 1.8L turbocharged gasoline engine incorporates infinitely variable intake and outlet control timing and direct fuel injection utilizing piezo injectors centrally located. In addition, this engine uses a prototype FEV engine control system, with software that was developed and adapted entirely by FEV. The vehicle features a 160 kW engine with a maximum mean effective pressure of 22.4 bar and 34 \% savings in simulated fuel consumption. During the first stage, a new electrohydraulically actuated hybrid transmission with seven forward gears and one reverse gear and a single dry starting clutch will be integrated. The electric motor of the hybrid is directly connected to the gear set of the transmission. Utilizing the special gear set layout, the electric motor can provide boost during a change of gears, so that there is no interruption in traction. Therefore, the transmission system combines the advantages of a double clutch controlled gear change (gear change without an interruption in traction) with the efficient, cost-effective design of an automated manual transmission system. Additionally, the transmission provides a purely electric drive system and the operation of an air-conditioning compressor during the engine stop phases. One other alternative is through the use of CAI (Controlled Auto Ignition), which incorporates a process developed by FEV for controlled compression ignition.}, language = {en} } @article{KezerashviliDachwald2021, author = {Kezerashvili, Roman Ya and Dachwald, Bernd}, title = {Preface: Solar sailing: Concepts, technology, and missions II}, series = {Advances in Space Research}, volume = {67}, journal = {Advances in Space Research}, number = {9}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0273-1177}, doi = {10.1016/j.asr.2021.01.037}, pages = {2559 -- 2560}, year = {2021}, language = {en} } @article{KhayyamJamaliBabHadiasharetal.2020, author = {Khayyam, Hamid and Jamali, Ali and Bab-Hadiashar, Alireza and Esch, Thomas and Ramakrishna, Seeram and Jalil, Mahdi and Naebe, Minoo}, title = {A Novel Hybrid Machine Learning Algorithm for Limited and Big Data Modelling with Application in Industry 4.0}, series = {IEEE Access}, journal = {IEEE Access}, publisher = {IEEE}, address = {New York, NY}, isbn = {2169-3536}, doi = {10.1109/ACCESS.2020.2999898}, pages = {1 -- 12}, year = {2020}, abstract = {To meet the challenges of manufacturing smart products, the manufacturing plants have been radically changed to become smart factories underpinned by industry 4.0 technologies. The transformation is assisted by employment of machine learning techniques that can deal with modeling both big or limited data. This manuscript reviews these concepts and present a case study that demonstrates the use of a novel intelligent hybrid algorithms for Industry 4.0 applications with limited data. In particular, an intelligent algorithm is proposed for robust data modeling of nonlinear systems based on input-output data. In our approach, a novel hybrid data-driven combining the Group-Method of Data-Handling and Singular-Value Decomposition is adapted to find an offline deterministic model combined with Pareto multi-objective optimization to overcome the overfitting issue. An Unscented-Kalman-Filter is also incorporated to update the coefficient of the deterministic model and increase its robustness against data uncertainties. The effectiveness of the proposed method is examined on a set of real industrial measurements.}, language = {en} } @article{KhayyamJamaliBabHadiasharetal.2020, author = {Khayyam, Hamid and Jamali, Ali and Bab-Hadiashar, Alireza and Esch, Thomas and Ramakrishna, Seeram and Jalili, Mahdi and Naebe, Minoo}, title = {A Novel Hybrid Machine Learning Algorithm for Limited and Big Data Modeling with Application in Industry 4.0}, series = {IEEE Access}, volume = {8}, journal = {IEEE Access}, number = {Art. 9108222}, publisher = {IEEE}, address = {New York, NY}, issn = {2169-3536}, doi = {10.1109/ACCESS.2020.2999898}, pages = {111381 -- 111393}, year = {2020}, abstract = {To meet the challenges of manufacturing smart products, the manufacturing plants have been radically changed to become smart factories underpinned by industry 4.0 technologies. The transformation is assisted by employment of machine learning techniques that can deal with modeling both big or limited data. This manuscript reviews these concepts and present a case study that demonstrates the use of a novel intelligent hybrid algorithms for Industry 4.0 applications with limited data. In particular, an intelligent algorithm is proposed for robust data modeling of nonlinear systems based on input-output data. In our approach, a novel hybrid data-driven combining the Group-Method of Data-Handling and Singular-Value Decomposition is adapted to find an offline deterministic model combined with Pareto multi-objective optimization to overcome the overfitting issue. An Unscented-Kalman-Filter is also incorporated to update the coefficient of the deterministic model and increase its robustness against data uncertainties. The effectiveness of the proposed method is examined on a set of real industrial measurements.}, language = {en} } @inproceedings{KleineKallweitMichauxetal.2016, author = {Kleine, Harald and Kallweit, Stephan and Michaux, Frank and Havermann, Marc and Olivier, Herbert}, title = {PIV Measurement of Shock Wave Diffraction}, series = {18th International Symposium on Applications of Laser Techniques to Fluid Mechanics, 2016, Lissabon}, booktitle = {18th International Symposium on Applications of Laser Techniques to Fluid Mechanics, 2016, Lissabon}, pages = {1 -- 14}, year = {2016}, language = {en} } @article{KochBoehnischVerdoncketal.2024, author = {Koch, Christopher and B{\"o}hnisch, Nils and Verdonck, Hendrik and Hach, Oliver and Braun, Carsten}, title = {Comparison of unsteady low- and mid-fidelity propeller aerodynamic methods for whirl flutter applications}, series = {Applied Sciences}, volume = {14}, journal = {Applied Sciences}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app14020850}, pages = {1 -- 28}, year = {2024}, abstract = {Aircraft configurations with propellers have been drawing more attention in recent times, partly due to new propulsion concepts based on hydrogen fuel cells and electric motors. These configurations are prone to whirl flutter, which is an aeroelastic instability affecting airframes with elastically supported propellers. It commonly needs to be mitigated already during the design phase of such configurations, requiring, among other things, unsteady aerodynamic transfer functions for the propeller. However, no comprehensive assessment of unsteady propeller aerodynamics for aeroelastic analysis is available in the literature. This paper provides a detailed comparison of nine different low- to mid-fidelity aerodynamic methods, demonstrating their impact on linear, unsteady aerodynamics, as well as whirl flutter stability prediction. Quasi-steady and unsteady methods for blade lift with or without coupling to blade element momentum theory are evaluated and compared to mid-fidelity potential flow solvers (UPM and DUST) and classical, derivative-based methods. Time-domain identification of frequency-domain transfer functions for the unsteady propeller hub loads is used to compare the different methods. Predictions of the minimum required pylon stiffness for stability show good agreement among the mid-fidelity methods. The differences in the stability predictions for the low-fidelity methods are higher. Most methods studied yield a more unstable system than classical, derivative-based whirl flutter analysis, indicating that the use of more sophisticated aerodynamic modeling techniques might be required for accurate whirl flutter prediction.}, language = {en} } @inproceedings{KohlbergerWildKasperetal.2021, author = {Kohlberger, David-Sharif and Wild, Dominik and Kasper, Stefan and Czupalla, Markus}, title = {Modeling and analyses of a thermal passively stabilized LEO/GEO star tracker with embedded phase change material applying the Infused Thermal Solutions (ITS) method}, series = {ICES202: Satellite, Payload, and Instrument Thermal Control}, booktitle = {ICES202: Satellite, Payload, and Instrument Thermal Control}, publisher = {Texas Tech University}, address = {Lubbock, Tex.}, pages = {12 Seiten}, year = {2021}, abstract = {Phase change materials offer a way of storing excess heat and releasing it when it is needed. They can be utilized as a method to control thermal behavior without the need for additional energy. This work focuses on exploring the potential of using phase change materials to passively control the thermal behavior of a star tracker by infusing it with a fitting phase change material. Based on the numerical model of the star trackers thermal behavior using ESATAN-TMS without implemented phase change material, a fitting phase change material for selected orbits is chosen and implemented in the thermal model. The altered thermal behavior of the numerical model after the implementation is analyzed for different amounts of the chosen phase change materials using an ESATAN-based subroutine developed by the FH Aachen. The PCM-modelling-subroutine is explained in the paper ICES-2021-110. The results show that an increasing amount of phase change material increasingly damps temperature oscillations. Using an integral part structure some of the mass increase can be compensated.}, language = {en} } @inproceedings{KonstantinidisDachwaldOhndorfetal.2013, author = {Konstantinidis, K. and Dachwald, Bernd and Ohndorf, A. and Dykta, P. and Voigt, K. and F{\"o}rstner, R.}, title = {Enceladus explorer (ENEX): A lander mission to probe subglacial water pockets on Saturn's moon enceladus for life}, series = {64th International Astronautical Congress 2013 (IAC 2013) : Beijing, China, 23 - 27 September 2013. (Proceedings of the International Astronautical Congress, IAC ; 2)}, booktitle = {64th International Astronautical Congress 2013 (IAC 2013) : Beijing, China, 23 - 27 September 2013. (Proceedings of the International Astronautical Congress, IAC ; 2)}, publisher = {Curran}, address = {Red Hook, NY}, organization = {International Astronautical Congress <64, 2013, Beijing>}, isbn = {978-1-62993-909-4}, pages = {1340 -- 1350}, year = {2013}, language = {en} } @inproceedings{KonstantinidisKowalskiMartinezetal.2015, author = {Konstantinidis, K. and Kowalski, Julia and Martinez, C. F. and Dachwald, Bernd and Ewerhart, D. and F{\"o}rstner, R.}, title = {Some necessary technologies for in-situ astrobiology on enceladus}, series = {Proceedings of the International Astronautical Congress}, booktitle = {Proceedings of the International Astronautical Congress}, isbn = {978-151081893-4}, pages = {1354 -- 1372}, year = {2015}, language = {en} } @article{KonstantinidisFloresMartinezDachwaldetal.2015, author = {Konstantinidis, Konstantinos and Flores Martinez, Claudio and Dachwald, Bernd and Ohndorf, Andreas and Dykta, Paul and Bowitz, Pascal and Rudolph, Martin and Digel, Ilya and Kowalski, Julia and Voigt, Konstantin and F{\"o}rstner, Roger}, title = {A lander mission to probe subglacial water on Saturn's moon enceladus for life}, series = {Acta astronautica}, volume = {Vol. 106}, journal = {Acta astronautica}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-2030 (E-Journal); 0094-5765 (Print)}, pages = {63 -- 89}, year = {2015}, language = {en} } @inproceedings{KorschDafnisReimerdesetal.2006, author = {Korsch, Helge and Dafnis, Athanasios and Reimerdes, Hans-G{\"u}nther and Braun, Carsten and Ballmann, Josef}, title = {Dynamic qualification of the HIRENASD elastic wing model}, series = {Motto: Luft- und Raumfahrt: Lehre, Forschung, Industrie - gemeinsam innovativ. Deutscher Luft- und Raumfahrtkongress 2006 : Braunschweig, 06. bis 09. November 2006. Jahrbuch / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt. 2006}, booktitle = {Motto: Luft- und Raumfahrt: Lehre, Forschung, Industrie - gemeinsam innovativ. Deutscher Luft- und Raumfahrtkongress 2006 : Braunschweig, 06. bis 09. November 2006. Jahrbuch / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt. 2006}, publisher = {Dt. Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth (DGLR)}, address = {Bonn}, pages = {1441 -- 1450}, year = {2006}, language = {en} } @phdthesis{Kowalski2008, author = {Kowalski, Julia}, title = {Two-phase Modeling of Debris Flows}, publisher = {Mensch und Buch}, address = {Berlin}, isbn = {978-3-86664-524-0}, pages = {148}, year = {2008}, language = {en} } @inproceedings{Kowalski2006, author = {Kowalski, Julia}, title = {Numerical Debris Flow Simulation}, series = {Schweizer Numerik Kolloquium : Book of Abstracts 12. April 2006}, booktitle = {Schweizer Numerik Kolloquium : Book of Abstracts 12. April 2006}, pages = {1}, year = {2006}, language = {en} } @inproceedings{KowalskiBarteltMcElwaine2007, author = {Kowalski, Julia and Bartelt, Perry and McElwaine, J.}, title = {Two-phase debris flow modeling}, series = {Geophysical Research Abstracts}, booktitle = {Geophysical Research Abstracts}, year = {2007}, language = {en} } @article{KowalskiLinderZierkeetal.2016, author = {Kowalski, Julia and Linder, Peter and Zierke, S. and Wulfen, B. van and Clemens, J. and Konstantinidis, K. and Ameres, G. and Hoffmann, R. and Mikucki, J. and Tulaczyk, S. and Funke, O. and Blandfort, D. and Espe, Clemens and Feldmann, Marco and Francke, Gero and Hiecker, S. and Plescher, Engelbert and Sch{\"o}ngarth, Sarah and Dachwald, Bernd and Digel, Ilya and Artmann, Gerhard and Eliseev, D. and Heinen, D. and Scholz, F. and Wiebusch, C. and Macht, S. and Bestmann, U. and Reineking, T. and Zetzsche, C. and Schill, K. and F{\"o}rstner, R. and Niedermeier, H. and Szumski, A. and Eissfeller, B. and Naumann, U. and Helbing, K.}, title = {Navigation technology for exploration of glacier ice with maneuverable melting probes}, series = {Cold Regions Science and Technology}, journal = {Cold Regions Science and Technology}, number = {123}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0165-232X}, doi = {10.1016/j.coldregions.2015.11.006}, pages = {53 -- 70}, year = {2016}, abstract = {The Saturnian moon Enceladus with its extensive water bodies underneath a thick ice sheet cover is a potential candidate for extraterrestrial life. Direct exploration of such extraterrestrial aquatic ecosystems requires advanced access and sampling technologies with a high level of autonomy. A new technological approach has been developed as part of the collaborative research project Enceladus Explorer (EnEx). The concept is based upon a minimally invasive melting probe called the IceMole. The force-regulated, heater-controlled IceMole is able to travel along a curved trajectory as well as upwards. Hence, it allows maneuvers which may be necessary for obstacle avoidance or target selection. Maneuverability, however, necessitates a sophisticated on-board navigation system capable of autonomous operations. The development of such a navigational system has been the focal part of the EnEx project. The original IceMole has been further developed to include relative positioning based on in-ice attitude determination, acoustic positioning, ultrasonic obstacle and target detection integrated through a high-level sensor fusion. This paper describes the EnEx technology and discusses implications for an actual extraterrestrial mission concept.}, language = {en} } @inproceedings{KowalskiMcArdellBartelt2006, author = {Kowalski, Julia and McArdell, B. W. and Bartelt, Perry}, title = {A comparison of two approaches to modeling multiphase gravity currents}, series = {Geophysical Research Abstracts}, volume = {8}, booktitle = {Geophysical Research Abstracts}, year = {2006}, language = {en} } @inproceedings{KowalskiMcElwaine2008, author = {Kowalski, Julia and McElwaine, J.}, title = {Two-phase debris flow modeling}, series = {Geophysical Research Abstracts}, booktitle = {Geophysical Research Abstracts}, year = {2008}, language = {en} } @article{KowalskiMcElwaine2013, author = {Kowalski, Julia and McElwaine, Jim N.}, title = {Shallow two-component gravity-driven flows with vertical variation}, series = {Journal of Fluid Mechanics}, volume = {714}, journal = {Journal of Fluid Mechanics}, publisher = {Cambridge Univ. Press}, address = {Cambridge}, isbn = {0022-1120}, pages = {434 -- 462}, year = {2013}, language = {en} } @inproceedings{KreyerEsch2017, author = {Kreyer, J{\"o}rg and Esch, Thomas}, title = {Simulation Tool for Predictive Control Strategies for an ORCSystem in Heavy Duty Vehicles}, series = {European GT Conference 2017}, booktitle = {European GT Conference 2017}, pages = {16 Seiten}, year = {2017}, abstract = {Scientific questions - How can a non-stationary heat offering in the commercial vehicle be used to reduce fuel consumption? - Which potentials offer route and environmental information among with predicted speed and load trajectories to increase the efficiency of a ORC-System? Methods - Desktop bound holistic simulation model for a heavy duty truck incl. an ORC System - Prediction of massflows, temperatures and mixture quality (AFR) of exhaust gas}, language = {en} } @article{KreyerMuellerEsch2020, author = {Kreyer, J{\"o}rg and M{\"u}ller, Marvin and Esch, Thomas}, title = {A Calculation Methodology for Predicting Exhaust Mass Flows and Exhaust Temperature Profiles for Heavy-Duty Vehicles}, series = {SAE International Journal of Commercial Vehicles}, volume = {13}, journal = {SAE International Journal of Commercial Vehicles}, number = {2}, publisher = {SAE International}, address = {Warrendale, Pa.}, issn = {1946-3928}, doi = {10.4271/02-13-02-0009}, pages = {129 -- 143}, year = {2020}, abstract = {The predictive control of commercial vehicle energy management systems, such as vehicle thermal management or waste heat recovery (WHR) systems, are discussed on the basis of information sources from the field of environment recognition and in combination with the determination of the vehicle system condition. In this article, a mathematical method for predicting the exhaust gas mass flow and the exhaust gas temperature is presented based on driving data of a heavy-duty vehicle. The prediction refers to the conditions of the exhaust gas at the inlet of the exhaust gas recirculation (EGR) cooler and at the outlet of the exhaust gas aftertreatment system (EAT). The heavy-duty vehicle was operated on the motorway to investigate the characteristic operational profile. In addition to the use of road gradient profile data, an evaluation of the continuously recorded distance signal, which represents the distance between the test vehicle and the road user ahead, is included in the prediction model. Using a Fourier analysis, the trajectory of the vehicle speed is determined for a defined prediction horizon. To verify the method, a holistic simulation model consisting of several hierarchically structured submodels has been developed. A map-based submodel of a combustion engine is used to determine the EGR and EAT exhaust gas mass flows and exhaust gas temperature profiles. All simulation results are validated on the basis of the recorded vehicle and environmental data. Deviations from the predicted values are analyzed and discussed.}, language = {en} } @inproceedings{KreyerMuellerEsch2020, author = {Kreyer, J{\"o}rg and M{\"u}ller, Marvin and Esch, Thomas}, title = {A Map-Based Model for the Determination of Fuel Consumption for Internal Combustion Engines as a Function of Flight Altitude}, publisher = {DGLR}, address = {Bonn}, doi = {10.25967/490162}, pages = {13 Seiten}, year = {2020}, abstract = {In addition to very high safety and reliability requirements, the design of internal combustion engines (ICE) in aviation focuses on economic efficiency. The objective must be to design the aircraft powertrain optimized for a specific flight mission with respect to fuel consumption and specific engine power. Against this background, expert tools provide valuable decision-making assistance for the customer. In this paper, a mathematical calculation model for the fuel consumption of aircraft ICE is presented. This model enables the derivation of fuel consumption maps for different engine configurations. Depending on the flight conditions and based on these maps, the current and the integrated fuel consumption for freely definable flight emissions is calculated. For that purpose, an interpolation method is used, that has been optimized for accuracy and calculation time. The mission boundary conditions flight altitude and power requirement of the ICE form the basis for this calculation. The mathematical fuel consumption model is embedded in a parent program. This parent program presents the simulated fuel consumption by means of an example flight mission for a representative airplane. The focus of the work is therefore on reproducing exact consumption data for flight operations. By use of the empirical approaches according to Gagg-Farrar [1] the power and fuel consumption as a function of the flight altitude are determined. To substantiate this approaches, a 1-D ICE model based on the multi-physical simulation tool GT-Suite® has been created. This 1-D engine model offers the possibility to analyze the filling and gas change processes, the internal combustion as well as heat and friction losses for an ICE under altitude environmental conditions. Performance measurements on a dynamometer at sea level for a naturally aspirated ICE with a displacement of 1211 ccm used in an aviation aircraft has been done to validate the 1-D ICE model. To check the plausibility of the empirical approaches with respect to the fuel consumption and performance adjustment for the flight altitude an analysis of the ICE efficiency chain of the 1-D engine model is done. In addition, a comparison of literature and manufacturer data with the simulation results is presented.}, language = {en} } @inproceedings{KronigerHorikawaFunkeetal.2021, author = {Kroniger, Daniel and Horikawa, Atsushi and Funke, Harald and Pf{\"a}ffle, Franziska}, title = {Numerical investigation of micromix hydrogen flames at different combustor pressure levels}, series = {The Proceedings of the International Conference on Power Engineering (ICOPE)}, booktitle = {The Proceedings of the International Conference on Power Engineering (ICOPE)}, doi = {10.1299/jsmeicope.2021.15.2021-0237}, pages = {4 Seiten}, year = {2021}, abstract = {This study investigates the influence of pressure on the temperature distribution of the micromix (MMX) hydrogen flame and the NOx emissions. A steady computational fluid dynamic (CFD) analysis is performed by simulating a reactive flow with a detailed chemical reaction model. The numerical analysis is validated based on experimental investigations. A quantitative correlation is parametrized based on the numerical results. We find, that the flame initiation point shifts with increasing pressure from anchoring behind a downstream located bluff body towards anchoring upstream at the hydrogen jet. The numerical NOx emissions trend regarding to a variation of pressure is in good agreement with the experimental results. The pressure has an impact on both, the residence time within the maximum temperature region and on the peak temperature itself. In conclusion, the numerical model proved to be adequate for future prototype design exploration studies targeting on improving the operating range.}, language = {en} } @inproceedings{KronigerHorikawaFunkeetal.2021, author = {Kroniger, Daniel and Horikawa, Atsushi and Funke, Harald and Pf{\"a}ffle, Franziska and Kishimoto, Tsuyoshi and Okada, Koichi}, title = {Experimental and numerical investigation on the effect of pressure on micromix hydrogen combustion}, series = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 3A: Combustion, Fuels, and Emissions}, booktitle = {Conference Proceedings Turbo Expo: Power for Land, Sea and Air, Volume 3A: Combustion, Fuels, and Emissions}, publisher = {ASME}, address = {New York, NY}, doi = {10.1115/GT2021-58926}, pages = {11 Seiten}, year = {2021}, abstract = {The micromix (MMX) combustion concept is a DLN gas turbine combustion technology designed for high hydrogen content fuels. Multiple non-premixed miniaturized flames based on jet in cross-flow (JICF) are inherently safe against flashback and ensure a stable operation in various operative conditions. The objective of this paper is to investigate the influence of pressure on the micromix flame with focus on the flame initiation point and the NOx emissions. A numerical model based on a steady RANS approach and the Complex Chemistry model with relevant reactions of the GRI 3.0 mechanism is used to predict the reactive flow and NOx emissions at various pressure conditions. Regarding the turbulence-chemical interaction, the Laminar Flame Concept (LFC) and the Eddy Dissipation Concept (EDC) are compared. The numerical results are validated against experimental results that have been acquired at a high pressure test facility for industrial can-type gas turbine combustors with regard to flame initiation and NOx emissions. The numerical approach is adequate to predict the flame initiation point and NOx emission trends. Interestingly, the flame shifts its initiation point during the pressure increase in upstream direction, whereby the flame attachment shifts from anchoring behind a downstream located bluff body towards anchoring directly at the hydrogen jet. The LFC predicts this change and the NOx emissions more accurately than the EDC. The resulting NOx correlation regarding the pressure is similar to a non-premixed type combustion configuration.}, language = {en} } @article{KraemerDaabMuelleretal.2013, author = {Kr{\"a}mer, Stefan and Daab, Dominique Jonas and M{\"u}ller, Brigitte and Wagner, Tobias and Baader, Fabian and Hessel, Joana and Gdalewitsch, Georg and Plescher, Engelbert and Dachwald, Bernd and Wahle, Michael and Gierse, Andreas and Vetter, Rudolf and Pf{\"u}tzenreuter, Lysan}, title = {Development and flight-testing of a system to isolate vibrations for microgravity experiments on sounding rockets}, series = {21st ESA Symposium on Rocket and Balloon Research}, journal = {21st ESA Symposium on Rocket and Balloon Research}, pages = {1 -- 8}, year = {2013}, language = {en} } @article{LeipoldFichtnerHeberetal.2006, author = {Leipold, M. and Fichtner, H. and Heber, B. and Groepper, P. and Lascar, S. and Burger, F. and Eiden, M. and Niederstadt, T. and Sickinger, C. and Herbeck, L. and Dachwald, Bernd and Seboldt, Wolfgang}, title = {Heliopause Explorer - A Sailcraft Mission to the Outer Boundaries of the Solar System}, series = {Acta Astronautica. 59 (2006), H. 8-11}, journal = {Acta Astronautica. 59 (2006), H. 8-11}, isbn = {0094-5765}, pages = {786 -- 796}, year = {2006}, language = {en} } @article{LettiniHavermannGuidettietal.2010, author = {Lettini, Antonio and Havermann, Marc and Guidetti, Marco and Fornaciari, Andrea}, title = {Improved functionalities and energy saving potential on mobile machines combining electronics with flow sharing valve and variable displacement pump}, series = {IFK 7, 7th International Fluid Power Conference, Efficiency through Fluid Power, 7. Internationales Fluidtechnisches Kolloquium, Workshop Proceedings, Vol. 3, Aachen, DE, 22.-24. Mar, 2010}, journal = {IFK 7, 7th International Fluid Power Conference, Efficiency through Fluid Power, 7. Internationales Fluidtechnisches Kolloquium, Workshop Proceedings, Vol. 3, Aachen, DE, 22.-24. Mar, 2010}, publisher = {-}, isbn = {978-3-940565-92-1}, pages = {103 -- 114}, year = {2010}, language = {en} } @article{LeyPlescherScholzetal.2007, author = {Ley, Wilfried and Plescher, Engelbert and Scholz, Artur and Piepenbrock, Johannes}, title = {COMPASS-1 picosatellite project / Ley, Wilfried ; Plescher, Engelbert ; Scholz, Artur ; Piepenbrock, Johannes}, series = {Small satellites for earth observation : digest of the 6th International symposium of the International Academy of Astronautics, Berlin, April 23 - 26, 2007 / ed. by Rainer Sandau; Hans-Peter R{\"o}ser; Arnoldo Valenzuela}, journal = {Small satellites for earth observation : digest of the 6th International symposium of the International Academy of Astronautics, Berlin, April 23 - 26, 2007 / ed. by Rainer Sandau; Hans-Peter R{\"o}ser; Arnoldo Valenzuela}, publisher = {Wissenschaft und Technik Verl.}, address = {Berlin}, isbn = {9783896855718}, pages = {147 -- 150}, year = {2007}, language = {en} } @book{LeyWittmannHallmann2009, author = {Ley, Wilfried and Wittmann, Klaus and Hallmann, Willi}, title = {Handbook of space technology}, publisher = {Wiley}, address = {Chichester}, isbn = {978-0-470-69739-9}, pages = {XIII, 882 S. : Ill., graph. Darst.}, year = {2009}, language = {en} } @inproceedings{LoebSchartnerDachwaldetal.2011, author = {Loeb, Horst W. and Schartner, Karl-Heinz and Dachwald, Bernd and Ohndorf, Andreas and Seboldt, Wolfgang}, title = {An Interstellar - Heliopause mission using a combination of solar/radioisotope electric propulsion}, series = {Presented at the 32nd International Electric Propulsion Conference}, booktitle = {Presented at the 32nd International Electric Propulsion Conference}, pages = {1 -- 7}, year = {2011}, abstract = {There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft travelling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by ESA.Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope electric propulsion. As a further alternative, we here investigate a combination of solar-electric propulsion and radioisotope-electric propulsion. The solar-electric propulsion stage consists of six 22 cm diameter "RIT-22"ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW BOM is provided by a light-weight solar array. The REP-stage consists of four space-proven 10 cm diameter "RIT-10" ion thrusters that will be operating one after the other for 9 yrs in total. Four advanced radioisotope generators provide 648 W at BOM. The scientific instrument package is oriented at earlier studies. For its mass and electric power requirement 35 kg and 35 W are assessed, respectively. Optimized trajectory calculations, treated in a separate contribution, are based on our "InTrance" method.The program yields a burn out of the REP stage in a distance of 79.6 AU for a usage of 154 kg of Xe propellant. With a C3 = 45,1 (km/s)2 a heliocentric probe velocity of 10 AU/yr is reached at this distance, provided a close Jupiter gravity assist adds a velocity increment of 2.7 AU/yr. A transfer time of 23.8 yrs results for this scenario requiring about 450 kg Xe for the SEP stage, jettisoned at 3 AU. We interpret the SEP/REP propulsion as a competing alternative to solar sail and ballistic/REP propulsion. Omiting a Jupiter fly-by even allows more launch flexibility, leaving the mission duration in the range of the ESA specification.}, language = {en} } @inproceedings{LoebSchartnerSeboldtetal.2006, author = {Loeb, Horst W. and Schartner, Karl-Heinz and Seboldt, Wolfgang and Dachwald, Bernd and Streppel, Joern and Meusemann, Hans and Sch{\"u}lke, Peter}, title = {SEP for a lander mission to the jovian moon europa}, series = {57th International Astronautical Congress}, booktitle = {57th International Astronautical Congress}, doi = {10.2514/6.IAC-06-C4.4.04}, pages = {1 -- 12}, year = {2006}, abstract = {Under DLR-contract, Giessen University and DLR Cologne are studying solar-electric propulsion missions (SEP) to the outer regions of the solar system. The most challenging reference mission concerns the transport of a 1.35-tons chemical lander spacecraft into an 80-RJ circular orbit around Jupiter, which would enable to place a 375 kg lander with 50 kg of scientific instruments on the surface of the icy moon "Europa". Thorough analyses show that the best solution in terms of SEP launch mass times thrusting time would be a two-stage EP module and a triple-junction solar array with concentrators which would be deployed step by step. Mission performance optimizations suggest to propel the spacecraft in the first EP stage by 6 gridded ion thrusters, running at 4.0 kV of beam voltage, which would save launch mass, and in the second stage by 4 thrusters with 1.25 to 1.5 kV of positive high voltage saving thrusting time. In this way, the launch mass of the spacecraft would be kept within 5.3 tons. Without a launcher's C3 and interplanetary gravity assists, Jupiter might be reached within about 4 yrs. The spiraling-down into the parking orbit would need another 1.8 yrs. This "large mission" can be scaled down to a smaller one, e.g., by halving all masses, the solar array power, and the number of thrusters. Due to their reliability, long lifetime and easy control, RIT-22 engines have been chosen for mission analysis. Based on precise tests, the thruster performance has been modeled.}, language = {en} } @article{LoebSchartnerDachwaldetal.2012, author = {Loeb, Horst Wolfgang and Schartner, Karl-Heinz and Dachwald, Bernd and Ohndorf, Andreas and Seboldt, Wolfgang}, title = {Interstellar heliopause probe}, series = {Труды МАИ}, journal = {Труды МАИ}, number = {60}, publisher = {Moskauer Staatliches Luftfahrtinstitut (МАИ)}, address = {Moskau}, pages = {2 -- 2}, year = {2012}, abstract = {There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft traveling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by European Space Agency (ESA). Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope-electric propulsion (REP). As a further alternative, we here investigate a combination of solar-electric propulsion (SEP) and REP. The SEP stage consists of six 22-cms diameter RIT-22 ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW at begin of mission (BOM) is provided by a lightweight solar array.}, language = {en} } @inproceedings{LoebSchartnerDachwaldetal.2007, author = {Loeb, Horst Wolfgang and Schartner, Karl-Heinz and Dachwald, Bernd and Seboldt, Wolfgang}, title = {SEP-Sample return from a main belt asteroid}, series = {30th International Electric Propulsion Conference}, booktitle = {30th International Electric Propulsion Conference}, pages = {1 -- 11}, year = {2007}, abstract = {By DLR-contact, sample return missions to the large main-belt asteroid "19, Fortuna" have been studied. The mission scenario has been based on three ion thrusters of the RIT-22 model, which is presently under space qualification, and on solar arrays equipped with triple-junction GaAs solar cells. After having designed the spacecraft, the orbit-to-orbit trajectories for both, a one-way SEP mission with a chemical sample return and an all-SEP return mission, have been optimized using a combination of artificial neural networks with evolutionary algorithms. Additionally, body-to-body trajectories have been investigated within a launch period between 2012 and 2015. For orbit-to-orbit calculation, the launch masses of the hybrid mission and of the all-SEP mission resulted in 2.05 tons and 1.56 tons, respectively, including a scientific payload of 246 kg. For the related transfer durations 4.14 yrs and 4.62 yrs were obtained. Finally, a comparison between the mission scenarios based on SEP and on NEP have been carried out favouring clearly SEP.}, language = {en} } @inproceedings{LudowicyRingsFingeretal.2018, author = {Ludowicy, Jonas and Rings, Ren{\´e} and Finger, Felix and Braun, Carsten}, title = {Sizing Studies of Light Aircraft with Serial Hybrid Propulsion Systems}, series = {Luft- und Raumfahrt - Digitalisierung und Vernetzung : Deutscher Luft- und Raumfahrtkongress 2018. 4. - 6. September 2018 - Friedrichshafen}, booktitle = {Luft- und Raumfahrt - Digitalisierung und Vernetzung : Deutscher Luft- und Raumfahrtkongress 2018. 4. - 6. September 2018 - Friedrichshafen}, pages = {11 S.}, year = {2018}, language = {en} } @inproceedings{LudowicyRingsFingeretal.2018, author = {Ludowicy, Jonas and Rings, Ren{\´e} and Finger, Felix and Braun, Carsten}, title = {Sizing Studies of Light Aircraft with Parallel Hybrid Propulsion Systems}, series = {Deutscher Luft- und Raumfahrtkongress 2018}, booktitle = {Deutscher Luft- und Raumfahrtkongress 2018}, doi = {10.25967/480227}, pages = {15 S.}, year = {2018}, language = {en} } @inproceedings{LudowicyRingsFingeretal.2019, author = {Ludowicy, Jonas and Rings, Ren{\´e} and Finger, Felix and Braun, Carsten and Bil, Cees}, title = {Impact of Propulsion Technology Levels on the Sizing and Energy Consumption for Serial HybridElectric General Aviation Aircraft}, series = {Asia Pacific International Symposium on Aerospace Technology. APISAT 2019}, booktitle = {Asia Pacific International Symposium on Aerospace Technology. APISAT 2019}, pages = {14 Seiten}, year = {2019}, language = {en} } @article{LyonsMikuckiGermanetal.2019, author = {Lyons, W. Berry and Mikucki, Jill A. and German, Laura A. and Welch, Kathleen A. and Welch, Susan A. and Gardener, Christopher B. and Tulaczyk, Slawek M. and Pettit, Erin C. and Kowalski, Julia and Dachwald, Bernd}, title = {The Geochemistry of Englacial Brine from Taylor Glacier, Antarctica}, series = {Journal of Geophysical Research: Biogeosciences}, journal = {Journal of Geophysical Research: Biogeosciences}, publisher = {Wiley}, address = {Hoboken}, issn = {2169-8961}, doi = {10.1029/2018JG004411}, year = {2019}, language = {en} } @incollection{MacdonaldMcGrathAppourchauxetal.2014, author = {Macdonald, Malcolm and McGrath, C. and Appourchaux, T. and Dachwald, Bernd and Finsterle, W. and Gizon, L. and Liewer, P. C. and McInnes, Colin R. and Mengali, G. and Seboldt, Wolfgang and Sekii, T. and Solanki, S. K. and Velli, M. and Wimmer-Schweingruber, R. F. and Spietz, Peter and Reinhard, Ruedeger}, title = {Gossamer roadmap technology reference study for a solar polar mission}, series = {Advances in solar sailing}, booktitle = {Advances in solar sailing}, editor = {Macdonald, Malcolm}, publisher = {Springer}, address = {Berlin, Heidelberg}, isbn = {978-3-642-34906-5}, doi = {10.1007/978-3-642-34907-2_17}, pages = {243 -- 257}, year = {2014}, abstract = {A technology reference study for a solar polar mission is presented. The study uses novel analytical methods to quantify the mission design space including the required sail performance to achieve a given solar polar observation angle within a given timeframe and thus to derive mass allocations for the remaining spacecraft sub-systems, that is excluding the solar sail sub-system. A parametric, bottom-up, system mass budget analysis is then used to establish the required sail technology to deliver a range of science payloads, and to establish where such payloads can be delivered to within a given timeframe. It is found that a solar polar mission requires a solar sail of side-length 100-125 m to deliver a 'sufficient value' minimum science payload, and that a 2.5 μm sail film substrate is typically required, however the design is much less sensitive to the boom specific mass.}, language = {en} } @misc{MachadoDahmannKeimeretal.2020, author = {Machado, Patricia Almeida and Dahmann, Peter and Keimer, Jona and Saretzki, Charlotte and St{\"u}bing, Felix and K{\"u}pper, Thomas}, title = {Stress profile and individual workload monitoring in general aviation pilots - an experiment's setting}, series = {23. Annual Meeting of the German Society of Travel Medicine, Coburg, 18.-19.9.2020}, journal = {23. Annual Meeting of the German Society of Travel Medicine, Coburg, 18.-19.9.2020}, doi = {10.55225/hppa.156}, year = {2020}, language = {en} } @article{MaiwaldDachwald2010, author = {Maiwald, Volker and Dachwald, Bernd}, title = {Mission Design for a Multiple-Rendezvous Mission to Jupiter's Trojans}, pages = {3}, year = {2010}, language = {en} } @article{MathiakPlescherWillnecker2005, author = {Mathiak, Gerhard and Plescher, Engelbert and Willnecker, Rainer}, title = {Liquid metal diffusion experiments in microgravity - Vibrational effects}, series = {Measurement science and technology}, volume = {Vol. 16}, journal = {Measurement science and technology}, number = {No. 2}, issn = {0957-0233}, doi = {10.1088/0957-0233/16/2/003}, pages = {336}, year = {2005}, language = {en} } @article{MathiakWillneckerPlescher2005, author = {Mathiak, Gerhard and Willnecker, Rainer and Plescher, Engelbert}, title = {Vibrational effects on diffusion experiments}, series = {Microgravity science and technology : international journal for microgravity research and applications}, volume = {Vol. 15}, journal = {Microgravity science and technology : international journal for microgravity research and applications}, number = {No. 1}, issn = {0938-0108}, pages = {295 -- 300}, year = {2005}, language = {en} } @article{Maurischat2022, author = {Maurischat, Andreas}, title = {Algebraic independence of the Carlitz period and its hyperderivatives}, series = {Journal of Number Theory}, volume = {240}, journal = {Journal of Number Theory}, publisher = {Elsevier}, address = {Orlando, Fla.}, issn = {0022-314X}, doi = {10.1016/j.jnt.2022.01.006}, pages = {145 -- 162}, year = {2022}, language = {en} } @article{Maurischat2021, author = {Maurischat, Andreas}, title = {Algebraic independence of the Carlitz period and its hyperderivatives}, pages = {1 -- 12}, year = {2021}, language = {en} } @article{MaurischatPerkins2020, author = {Maurischat, Andreas and Perkins, Rudolph}, title = {Taylor coefficients of Anderson generating functions and Drinfeld torsion extensions}, number = {Vol. 18, No. 01}, publisher = {World Scientific}, address = {Singapur}, doi = {10.1142/S1793042122500099}, pages = {113 -- 130}, year = {2020}, abstract = {We generalize our work on Carlitz prime power torsion extension to torsion extensions of Drinfeld modules of arbitrary rank. As in the Carlitz case, we give a description of these extensions in terms of evaluations of Anderson generating functions and their hyperderivatives at roots of unity. We also give a direct proof that the image of the Galois representation attached to the p-adic Tate module lies in the p-adic points of the motivic Galois group. This is a generalization of the corresponding result of Chang and Papanikolas for the t-adic case.}, language = {en} } @inproceedings{MayntzKeimerDahmannetal.2022, author = {Mayntz, Joscha and Keimer, Jona and Dahmann, Peter and Hille, Sebastian and Stumpf, Eike and Fisher, Alex and Dorrington, Graham}, title = {Electrical Drive and Regeneration in General Aviation Flight with Propellers}, series = {Deutscher Luft- und Raumfahrtkongress 2020}, booktitle = {Deutscher Luft- und Raumfahrtkongress 2020}, publisher = {DGLR}, address = {Bonn}, doi = {10.25967/530100}, pages = {8 Seiten}, year = {2022}, abstract = {Electric flight has the potential for a more sustainable and energy-saving way of aviation compared to fossil fuel aviation. The electric motor can be used as a generator inflight to regenerate energy during descent. Three different approaches to regenerating with electric propeller powertrains are proposed in this paper. The powertrain is to be set up in a wind tunnel to determine the propeller efficiency in both working modes as well as the noise emissions. Furthermore, the planned flight tests are discussed. In preparation for these tests, a yaw stability analysis is performed with the result that the aeroplane is controllable during flight and in the most critical failure case. The paper shows the potential for inflight regeneration and addresses the research gaps in the dual role of electric powertrains for propulsion and regeneration of general aviation aircraft.}, language = {en} } @misc{MayntzKeimerTegtmeyeretal.2021, author = {Mayntz, Joscha and Keimer, Jona and Tegtmeyer, Philipp and Dahmann, Peter and Hille, Sebastian and Stumpf, Eike and Fisher, Alex and Dorrington, Graham}, title = {Aerodynamic Investigation on Efficient Inflight Transition of a Propeller from Propulsion to Regeneration Mode}, series = {AIAA SCITECH 2022 Forum}, journal = {AIAA SCITECH 2022 Forum}, publisher = {AIAA}, address = {Reston, Va.}, doi = {10.2514/6.2022-0546}, year = {2021}, abstract = {This paper discusses a new way of inflight power regeneration for electric or hybrid-electric driven general aviation aircraft with one powertrain for both configurations. Three different approaches for the shift from propulsion to regeneration mode are analyzed. Numerical cal-culation and wind tunnel results are compared and show the highest regeneration potential for the "Windmill" approach, where the propeller blades are flipped, and rotation is reversed. A combination of all regeneration approaches for a realistic flight mission is discussed.}, language = {en} } @article{McArdellBarteltKowalski2007, author = {McArdell, Brian W. and Bartelt, Perry and Kowalski, Julia}, title = {Field observations of basal forces and fluid pore pressure in a debris flow}, series = {Geophysical Research Letters (GRL)}, volume = {34}, journal = {Geophysical Research Letters (GRL)}, number = {7}, isbn = {0094-8276}, year = {2007}, abstract = {Using results from an 8 m2 instrumented force plate we describe field measurements of normal and shear stresses, and fluid pore pressure for a debris flow. The flow depth increased from 0.1 to 1 m within the first 12 s of flow front arrival, remained relatively constant until 100 s, and then gradually decreased to 0.5 m by 600 s. Normal and shear stresses and pore fluid pressure varied in-phase with the flow depth. Calculated bulk densities are ρb = 2000-2250 kg m-3 for the bulk flow and ρf = 1600-1750 kg m-3 for the fluid phase. The ratio of effective normal stress to shear stress yields a Coulomb basal friction angle of ϕ = 26° at the flow front. We did not find a strong correlation between the degree of agitation in the flow, estimated using the signal from a geophone on the force plate, and an assumed dynamic pore fluid pressure. Our data support the idea that excess pore-fluid pressures are long lived in debris flows and therefore contribute to their unusual mobility.}, language = {en} } @incollection{McInnesBothmerDachwaldetal.2014, author = {McInnes, Colin R. and Bothmer, Volker and Dachwald, Bernd and Geppert, Ulrich R. M. E. and Heiligers, Jeannette and Hilgers, Alan and Johnson, Les and Macdonald, Malcolm and Reinhard, Ruedeger and Seboldt, Wolfgang and Spietz, Peter}, title = {Gossamer roadmap technology reference study for a Sub-L1 Space Weather Mission}, series = {Advances in solar sailing}, booktitle = {Advances in solar sailing}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-642-34906-5 (Print) ; 978-3-642-34907-2 (E-Book)}, pages = {227 -- 242}, year = {2014}, abstract = {A technology reference study for a displaced Lagrange point space weather mission is presented. The mission builds on previous concepts, but adopts a strong micro-spacecraft philosophy to deliver a low mass platform and payload which can be accommodated on the DLR/ESA Gossamer-3 technology demonstration mission. A direct escape from Geostationary Transfer Orbit is assumed with the sail deployed after the escape burn. The use of a miniaturized, low mass platform and payload then allows the Gossamer-3 solar sail to potentially double the warning time of space weather events. The mission profile and mass budgets will be presented to achieve these ambitious goals.}, language = {en} } @incollection{Mertens1997, author = {Mertens, Josef}, title = {Required aerodynamic technologies}, series = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, booktitle = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, editor = {Sobieczky, H.}, publisher = {Springer}, address = {Wien [u.a.]}, isbn = {3-2118-2815-X}, doi = {10.1007/978-3-7091-2658-5_5}, pages = {69 -- 96}, year = {1997}, abstract = {In the preceeding chapters on "Son of Concorde, a Technology Challenge" and "Aerodynamic Multipoint Design Challenge" it was explained, that a well balanced contribution of new technologies in all major disciplines is required for realisation of a new Supersonic Commercial Transport (SCT). One of these technologies - usually one of the most important for aircraft-is aerodynamics. Here, the required "pure" aerodynamic technologies are specified in more detail, according to our present knowledge. Increasing insight into the problems may change the balance of importance of the individual technologies and may require some more contributions. We must never confine our knowledge to the knowledge base of an expert at a given time, but must stay open for new insights.}, language = {en} } @incollection{Mertens1997, author = {Mertens, Josef}, title = {Certification of supersonic civil transports}, series = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, booktitle = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, editor = {Sobieczky, H.}, publisher = {Springer}, address = {Wien [u.a.]}, isbn = {3-2118-2815-X}, doi = {10.1007/978-3-7091-2658-5_6}, pages = {97 -- 103}, year = {1997}, abstract = {Since certification of Concorde new certification standards were introduced including many new regulations to improve flight safety. Most of these standards are to prevent severe accidents in the future which happened in the past (here: after Concorde's certification). A new SCT has to fulfill these standards, although Concorde had none of these accidents. But accidents - although they sometimes occurred only for a specific aircraft type - have to be avoided for any (new) aircraft. Because of existing aircraft without typical accident types having demonstrated their reliability, they are allowed to go on based on their old certification; although sometimes new rules prevent accident types which are not connected to specific aircraft types - like e.g. evacuation rules. Anyway, Concorde is allowed to fly based on its old certification, and hopefully in the future will fly as safely as in the past. But a new SCT has to fulfill updated rules like any other aircraft, and it has to be "just another aircraft" [75].}, language = {en} } @incollection{Mertens1997, author = {Mertens, Josef}, title = {Supersonic laminar flow}, series = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, booktitle = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, editor = {Sobieczky, H.}, publisher = {Springer}, address = {Wien [u.a.]}, isbn = {3-2118-2815-X}, doi = {10.1007/978-3-7091-2658-5_18}, pages = {275 -- 290}, year = {1997}, abstract = {Supersonic transports are very drag sensitive. Technology to reduce drag by application of laminar flow, therefore, will be important; it is a prerequisite to achieve very long range capability. In earlier studies it was assumed that SCTs would only become possible by application of laminar flow [376]. But today, we request an SCT to be viable without application of laminar flow in order to maintain its competitiveness when laminar flow becomes available for subsonic and supersonic transports. By reducing fuel burned, laminar flow drag reduction reduces size and weight of the aircraft, or increases range capability -whereas otherwise size and weight would grow towards infinity. Transition mechanisms from laminar to turbulent state of the boundary layer flow (ALT, CFI, TSI) function as for transonic transports, but at more severe conditions: higher sweep angles, cooled surfaces; higher mode instabilities (HMI) must at least be taken into account, although they may not become important below Mach 3. Hitherto there is a worldwide lack of ground test facilities to investigate TSI at the expected cruise Mach numbers between 1.6 and 2.4; in Stuttgart, Germany one such facility -a Ludwieg tube- is still in the validation phase. A quiet Ludwieg tunnel could be a favourable choice for Europe. But it will require a new approach in designing aircraft which includes improved theoretical predictions, usage of classical wind tunnels for turbulent flow and flight tests for validation.}, language = {en} } @incollection{Mertens1997, author = {Mertens, Josef}, title = {Son of Concorde, a technology challenge}, series = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, booktitle = {New design concepts for high speed air transport. - (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, editor = {Sobieczky, H.}, publisher = {Springer}, address = {Wien [u.a.]}, isbn = {3-2118-2815-X}, doi = {10.1007/978-3-7091-2658-5_3}, pages = {31 -- 51}, year = {1997}, abstract = {Concorde (Figure 9) is the only supersonic airliner which has been introduced into regular passenger service. It is still in service at British Airways and Air France without any flight accidents, and probably will stay in service for at least for ten more years.}, language = {en} } @incollection{Mertens1997, author = {Mertens, Josef}, title = {Aerodynamic multi point design challenge}, series = {New design concepts for high speed air transport.- (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, booktitle = {New design concepts for high speed air transport.- (Courses and lectures / International Centre for Mechanical Sciences ; 366)}, editor = {Sobieczky, H.}, publisher = {Springer}, address = {Wien [u.a.]}, isbn = {3-2118-2815-X}, doi = {10.1007/978-3-7091-2658-5_4}, pages = {53 -- 67}, year = {1997}, abstract = {In the chapter "Son of Concorde, a Technology Challenge" one of the new challenges for a Supersonic Commercial Transport (SCT) is multi-point design for the four main design points: - supersonic cruise - transonic cruise - take-off and landing - transonic acceleration.}, language = {en} } @inproceedings{Mertens2001, author = {Mertens, Josef}, title = {Next steps envisaged to improve wing performance of commercial aircraft}, series = {Aerodynamic drag reduction technologies : proceedings of the CEAS/DragNet European Drag Reduction Conference, 19-21 June 2000, Potsdam, Germany. - (Notes on numerical fluid mechanics ; 76)}, booktitle = {Aerodynamic drag reduction technologies : proceedings of the CEAS/DragNet European Drag Reduction Conference, 19-21 June 2000, Potsdam, Germany. - (Notes on numerical fluid mechanics ; 76)}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {3-540-41911-X (Print)}, doi = {10.1007/978-3-540-45359-8_26}, pages = {246 -- 255}, year = {2001}, language = {en} } @incollection{Mertens1997, author = {Mertens, Josef}, title = {Reduction of aerodynamic drag (RaWid)-Status after the first year of the program}, series = {New results in numerical and experimental fluid mechanics. - (Notes on numerical fluid mechanics ; 60)}, booktitle = {New results in numerical and experimental fluid mechanics. - (Notes on numerical fluid mechanics ; 60)}, publisher = {Vieweg}, address = {Braunschweig [u.a.]}, isbn = {3-528-06960-0}, doi = {10.1007/978-3-322-86573-1_2}, pages = {7 -- 14}, year = {1997}, abstract = {The technology programme "Reduction of aerodynamic drag (RaWid)" for high speed aerodynamics at Daimler-Benz Aerospace Airbus is sponsered by the German ministry for education, research and technology since July 1, 1995. Connected to this industrial programme are the cooperation programmes "MEGAFLOW" under leadership of the DLR and "Transition" by the DFG, and several contributions by DLR and universities. The programme is oriented towards technologies required for a MEGALINER which gains momentum by the ambitious plans for a new large Airbus A3XX. In the first year new technological steps were undertaken in theory, design and experiment. Some critical steps were verified by wing designs checked in wind tunnel tests.}, language = {en} } @article{Mertens1998, author = {Mertens, Josef}, title = {Required technologies for supersonic aircraft}, series = {Fluid dynamics research on supersonic aircraft : this report is a compilation of the edited proceedings of the special course on "Fluid dynamic research on supersonic aircraft" held at the Karman Institute for Fluid Dynamics (VKI) in Rhode-Saint-Genese, Belgium, 25-29 May 1998}, journal = {Fluid dynamics research on supersonic aircraft : this report is a compilation of the edited proceedings of the special course on "Fluid dynamic research on supersonic aircraft" held at the Karman Institute for Fluid Dynamics (VKI) in Rhode-Saint-Genese, Belgium, 25-29 May 1998}, publisher = {Research and Technology Organization}, address = {Neuilly-sur-Seine}, isbn = {92-837-1007-X}, pages = {5.1 -- 5.16}, year = {1998}, language = {en} } @article{Mertens1998, author = {Mertens, Josef}, title = {Multi point design challenges for supersonic transports}, series = {Fluid dynamics research on supersonic aircraft : this report is a compilation of the edited proceedings of the special course on "Fluid dynamics research on supersonic aircraft" held at the Karman Institute for Fluid Dynamics (VKI) in Rhode-Saint-Genese, Belgium, 25-29 May 1998}, journal = {Fluid dynamics research on supersonic aircraft : this report is a compilation of the edited proceedings of the special course on "Fluid dynamics research on supersonic aircraft" held at the Karman Institute for Fluid Dynamics (VKI) in Rhode-Saint-Genese, Belgium, 25-29 May 1998}, publisher = {Research and Technology Organization}, address = {Neuilly-sur-Seine}, isbn = {92-837-1007-X}, pages = {8.1 -- 8.12}, year = {1998}, language = {en} } @article{Mertens1992, author = {Mertens, Josef}, title = {Laminar flow for supersonic transports}, series = {Proceedings : March 16 - 18, 1992, Congress Centrum, Hamburg, Federal Republic of Germany / organized jointly by: Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt e.V. ... [Programme committee J. Szodruch ...]}, journal = {Proceedings : March 16 - 18, 1992, Congress Centrum, Hamburg, Federal Republic of Germany / organized jointly by: Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt e.V. ... [Programme committee J. Szodruch ...]}, publisher = {DGLR}, address = {Bonn}, isbn = {3-922010-73-3}, pages = {319 -- 323}, year = {1992}, language = {en} } @inproceedings{Mertens1999, author = {Mertens, Josef}, title = {Some important results of the technology programme RaWid}, series = {New Results in Numerical and Experimental Fluid Mechanics : Contributions to the 11th AG STAB/DGLR Symposium Berlin, Germany 1998. - Vol. 2. - (Notes on Numerical Fluid Mechanics ; 72)}, booktitle = {New Results in Numerical and Experimental Fluid Mechanics : Contributions to the 11th AG STAB/DGLR Symposium Berlin, Germany 1998. - Vol. 2. - (Notes on Numerical Fluid Mechanics ; 72)}, editor = {Nitsche, Wolfgang}, publisher = {Springer Fachmedien}, address = {Wiesbaden}, isbn = {978-3-663-10903-7 (Print)}, doi = {10.1007/978-3-663-10901-3_41}, pages = {315 -- 322}, year = {1999}, language = {en} } @incollection{MertensBecker1989, author = {Mertens, Josef and Becker, K.}, title = {Numerical solution of flow equations : an aircraft designer's view}, series = {Nonlinear hyperbolic equations - theory, computation methods, and applications : proceedings of the 2nd International Conference on Nonlinear Hyperbolic Problems, Aachen, FRG, March 14 to 18, 1988. - (Notes on Numerical Fluid Mechanics ; 24)}, booktitle = {Nonlinear hyperbolic equations - theory, computation methods, and applications : proceedings of the 2nd International Conference on Nonlinear Hyperbolic Problems, Aachen, FRG, March 14 to 18, 1988. - (Notes on Numerical Fluid Mechanics ; 24)}, editor = {Ballmann, Josef}, publisher = {Vieweg}, address = {Braunschweig}, isbn = {3-528-08098-1}, doi = {10.1007/978-3-322-87869-4_41}, pages = {403 -- 412}, year = {1989}, abstract = {Today the most accurate and cost effective industrial codes used in aircraft design are based on the full potential equation coupled with boundary layer equations. However, these are not capable to solve complicated three-dimensional problems of vortical flows and shocks. On the other hand Euler and Navier-Stokes codes are too expensive and not accurate enough for design purposes, especially in regard of drag and interference prediction. The reasons for these deficiencies are investigated and a way to overcome them by future developments is demonstrated.}, language = {en} } @article{MertensHenke2001, author = {Mertens, Josef and Henke, Rolf}, title = {Adaptive technologies for future civil air transport}, series = {Air \& Space Europe. 3 (2001), H. 3-4}, journal = {Air \& Space Europe. 3 (2001), H. 3-4}, isbn = {1247-5793}, pages = {80 -- 82}, year = {2001}, language = {en} } @article{MertensKlevenhusenJakob1987, author = {Mertens, Josef and Klevenhusen, K. D. and Jakob, H.}, title = {Accurate Transonic Wave Drag Prediction Using Simple Physical Models}, series = {AIAA-Journal. 25 (1987), H. 6}, journal = {AIAA-Journal. 25 (1987), H. 6}, isbn = {0001-1452}, pages = {799 -- 805}, year = {1987}, language = {en} } @misc{MertensLajain2002, author = {Mertens, Josef and Lajain, Henri}, title = {Method of fabricating leading edge nose structures of aerodynamic surfaces : patent no.: US 6,415,510 B2 ; date of patent: Jul. 9, 2002}, publisher = {United States Patent and Trademark Office}, address = {[Washington, DC]}, pages = {12 S. : Ill.}, year = {2002}, language = {en} } @book{MertensVeldenKelmetal.2000, author = {Mertens, Josef and Velden, Alexander van der and Kelm, Roland and Kokan, David}, title = {Application of MDO to large subsonic transport aircraft}, publisher = {American Institute of Aeronautics and Astronautics}, address = {Reston, Va.}, pages = {12 S. : zahlr. Ill. u. graph. Darst.}, year = {2000}, language = {en} } @article{MeyerGranrathFeyerletal.2021, author = {Meyer, Max-Arno and Granrath, Christian and Feyerl, G{\"u}nter and Richenhagen, Johannes and Kaths, Jakob and Andert, Jakob}, title = {Closed-loop platoon simulation with cooperative intelligent transportation systems based on vehicle-to-X communication}, series = {Simulation Modelling Practice and Theory}, volume = {106}, journal = {Simulation Modelling Practice and Theory}, number = {Art. 102173}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1569-190X}, doi = {10.1016/j.simpat.2020.102173}, year = {2021}, language = {en} } @article{MikuckiSchulerDigeletal.2023, author = {Mikucki, Jill Ann and Schuler, C. G. and Digel, Ilya and Kowalski, Julia and Tuttle, M. J. and Chua, Michelle and Davis, R. and Purcell, Alicia and Ghosh, D. and Francke, G. and Feldmann, M. and Espe, C. and Heinen, Dirk and Dachwald, Bernd and Clemens, Joachim and Lyons, W. B. and Tulaczyk, S.}, title = {Field-Based planetary protection operations for melt probes: validation of clean access into the blood falls, antarctica, englacial ecosystem}, series = {Astrobiology}, volume = {23}, journal = {Astrobiology}, number = {11}, publisher = {Liebert}, address = {New York, NY}, issn = {1557-8070 (online)}, doi = {10.1089/ast.2021.0102}, pages = {1165 -- 1178}, year = {2023}, abstract = {Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063\% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.}, language = {en} } @inproceedings{MulsowHuelsenGuetzlaffetal.2023, author = {Mulsow, Niklas A. and H{\"u}lsen, Benjamin and G{\"u}tzlaff, Joel and Spies, Leon and Bresser, Andreas and Dabrowski, Adam and Czupalla, Markus and Kirchner, Frank}, title = {Concept and design of an autonomous micro rover for long term lunar exploration}, series = {Proceedings of the 74th International Astronautical Congress}, booktitle = {Proceedings of the 74th International Astronautical Congress}, publisher = {dfki}, address = {Saarbr{\"u}cken}, pages = {13 Seiten}, year = {2023}, abstract = {Research on robotic lunar exploration has seen a broad revival, especially since the Google Lunar X-Prize increasingly brought private endeavors into play. This development is supported by national agencies with the aim of enabling long-term lunar infrastructure for in-situ operations and the establishment of a moon village. One challenge for effective exploration missions is developing a compact and lightweight robotic rover to reduce launch costs and open the possibility for secondary payload options. Existing micro rovers for exploration missions are clearly limited by their design for one day of sunlight and their low level of autonomy. For expanding the potential mission applications and range of use, an extension of lifetime could be reached by surviving the lunar night and providing a higher level of autonomy. To address this objective, the paper presents a system design concept for a lightweight micro rover with long-term mission duration capabilities, derived from a multi-day lunar mission scenario at equatorial regions. Technical solution approaches are described, analyzed, and evaluated, with emphasis put on the harmonization of hardware selection due to a strictly limited budget in dimensions and power.}, language = {en} } @inproceedings{MoehrenBergmannJanseretal.2023, author = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten}, title = {On the determination of harmonic propeller loads}, series = {AIAA SCITECH 2023 Forum}, booktitle = {AIAA SCITECH 2023 Forum}, publisher = {AIAA}, doi = {10.2514/6.2023-2404}, pages = {12 Seiten}, year = {2023}, abstract = {Dynamic loads significantly impact the structural design of propeller blades due to fatigue and static strength. Since propellers are elastic structures, deformations and aerodynamic loads are coupled. In the past, propeller manufacturers established procedures to determine unsteady aerodynamic loads and the structural response with analytical steady-state calculations. According to the approach, aeroelastic coupling primarily consists of torsional deformations. They neglect bending deformations, deformation velocities, and inertia terms. This paper validates the assumptions above for a General Aviation propeller and a lift propeller for urban air mobility or large cargo drones. Fully coupled reduced-order simulations determine the dynamic loads in the time domain. A quasi-steady blade element momentum approach transfers loads to one-dimensional finite beam elements. The simulation results are in relatively good agreement with the analytical method for the General Aviation propeller but show increasing errors for the slender lift propeller. The analytical approach is modified to consider the induced velocities. Still, inertia and velocity proportional terms play a significant role for the lift propeller due to increased elasticity. The assumption that only torsional deformations significantly impact the dynamic loads of propellers is not valid. Adequate determination of dynamic loads of such designs requires coupled aeroelastic simulations or advanced analytical procedures.}, language = {en} } @article{NeuJanserKhatibietal.2016, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Braun, Carsten and Orifici, Adrian C.}, title = {Operational Modal Analysis of a wing excited by transonic flow}, series = {Aerospace Science and Technology}, volume = {49}, journal = {Aerospace Science and Technology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1270-9638}, doi = {10.1016/j.ast.2015.11.032}, pages = {73 -- 79}, year = {2016}, abstract = {Operational Modal Analysis (OMA) is a promising candidate for flutter testing and Structural Health Monitoring (SHM) of aircraft wings that are passively excited by wind loads. However, no studies have been published where OMA is tested in transonic flows, which is the dominant condition for large civil aircraft and is characterized by complex and unique aerodynamic phenomena. We use data from the HIRENASD large-scale wind tunnel experiment to automatically extract modal parameters from an ambiently excited wing operated in the transonic regime using two OMA methods: Stochastic Subspace Identification (SSI) and Frequency Domain Decomposition (FDD). The system response is evaluated based on accelerometer measurements. The excitation is investigated from surface pressure measurements. The forcing function is shown to be non-white, non-stationary and contaminated by narrow-banded transonic disturbances. All these properties violate fundamental OMA assumptions about the forcing function. Despite this, all physical modes in the investigated frequency range were successfully identified, and in addition transonic pressure waves were identified as physical modes as well. The SSI method showed superior identification capabilities for the investigated case. The investigation shows that complex transonic flows can interfere with OMA. This can make existing approaches for modal tracking unsuitable for their application to aircraft wings operated in the transonic flight regime. Approaches to separate the true physical modes from the transonic disturbances are discussed.}, language = {en} } @inproceedings{NeuJanserKhatibietal.2015, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {Operational modal analysis of a cantilever in a wind tunnel using optical fiber bragg grating sensors}, series = {6th International Operational Modal Analysis Conference. IOMAC´15. 2015 May 12-14 Gijon - Spain}, booktitle = {6th International Operational Modal Analysis Conference. IOMAC´15. 2015 May 12-14 Gijon - Spain}, doi = {10.13140/RG.2.1.3753.0324}, pages = {10 S.}, year = {2015}, language = {en} } @inproceedings{NeuJanserKhatibietal.2016, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {In-flight vibration-based structural health monitoring of aircraft wings}, series = {30th Congress of the internatonal council of the aeronautical sciences : 25.-30. September 2016, Daejeon, Korea}, booktitle = {30th Congress of the internatonal council of the aeronautical sciences : 25.-30. September 2016, Daejeon, Korea}, pages = {10 Seiten}, year = {2016}, abstract = {This work presents a methodology for automated damage-sensitive feature extraction and anomaly detection under multivariate operational variability for in-flight assessment of wings. The method uses a passive excitation approach, i. e. without the need for artificial actuation. The modal system properties (natural frequencies and damping ratios) are used as damage-sensitive features. Special emphasis is placed on the use of Fiber Bragg Grating (FBG) sensing technology and the consideration of Operational and Environmental Variability (OEV). Measurements from a wind tunnel investigation with a composite cantilever equipped with FBG and piezoelectric sensors are used to successfully detect an impact damage. In addition, the feasibility of damage localisation and severity estimation is evaluated based on the coupling found between damageand OEV-induced feature changes.}, language = {en} } @article{NeuJanserKhatibietal.2017, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {Fully Automated Operational Modal Analysis using multi-stage clustering}, series = {Mechanical Systems and Signal Processing}, volume = {Vol. 84, Part A}, journal = {Mechanical Systems and Signal Processing}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0888-3270}, doi = {10.1016/j.ymssp.2016.07.031}, pages = {308 -- 323}, year = {2017}, language = {en} } @article{NeuJanserKhatibietal.2016, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {Automated modal parameter-based anomaly detection under varying wind excitation}, series = {Structural Health Monitoring}, volume = {15}, journal = {Structural Health Monitoring}, number = {6}, publisher = {Sage}, address = {London}, issn = {1475-9217}, doi = {10.1177/1475921716665803}, pages = {1 -- 20}, year = {2016}, abstract = {Wind-induced operational variability is one of the major challenges for structural health monitoring of slender engineering structures like aircraft wings or wind turbine blades. Damage sensitive features often show an even bigger sensitivity to operational variability. In this study a composite cantilever was subjected to multiple mass configurations, velocities and angles of attack in a controlled wind tunnel environment. A small-scale impact damage was introduced to the specimen and the structural response measurements were repeated. The proposed damage detection methodology is based on automated operational modal analysis. A novel baseline preparation procedure is described that reduces the amount of user interaction to the provision of a single consistency threshold. The procedure starts with an indeterminate number of operational modal analysis identifications from a large number of datasets and returns a complete baseline matrix of natural frequencies and damping ratios that is suitable for subsequent anomaly detection. Mahalanobis distance-based anomaly detection is then applied to successfully detect the damage under varying severities of operational variability and with various degrees of knowledge about the present operational conditions. The damage detection capabilities of the proposed methodology were found to be excellent under varying velocities and angles of attack. Damage detection was less successful under joint mass and wind variability but could be significantly improved through the provision of the currently encountered operational conditions.}, language = {en} } @inproceedings{NiedermeierClemensKowalskietal.2014, author = {Niedermeier, H. and Clemens, J. and Kowalski, Julia and Macht, S. and Heinen, D. and Hoffmann, R. and Linder, Peter}, title = {Navigation system for a research ice probe for antarctic glaciers}, series = {IEEE/ION Position, Location and Navigation Symposium (PLANS) ; 5-8 May 2014, Monterey, Calif.}, booktitle = {IEEE/ION Position, Location and Navigation Symposium (PLANS) ; 5-8 May 2014, Monterey, Calif.}, publisher = {IEEE}, address = {Piscataway, NJ}, organization = {Position, Location and Navigation Symposium <2014, Monterey, Calif.>}, isbn = {978-1-4799-3319-8}, pages = {959 -- 975}, year = {2014}, language = {en} } @inproceedings{NowackRoethBuehrigPolaczeketal.2008, author = {Nowack, N. and R{\"o}th, Thilo and B{\"u}hrig-Polaczek, A. and Klaus, G.}, title = {Advanced Sheet Metal Components Reinforced by Light Metal Cast Structures}, series = {Aluminium alloys : their physical and mechanical properties ; [proceedings of the 11th International Conference on Aluminium Alloys, 22 - 26 Sept. 2008, Aachen, Germany ; ICAA 11]}, booktitle = {Aluminium alloys : their physical and mechanical properties ; [proceedings of the 11th International Conference on Aluminium Alloys, 22 - 26 Sept. 2008, Aachen, Germany ; ICAA 11]}, number = {2}, editor = {Hirsch, J{\"u}rgen}, isbn = {978-3-527-32367-8}, pages = {2374 -- 2381}, year = {2008}, language = {en} } @inproceedings{OhndorfDachwaldSeboldtetal.2011, author = {Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang and Schartner, Karl-Heinz}, title = {Flight times to the heliopause using a combination of solar and radioisotope electric propulsion}, series = {32nd International Electric Propulsion Conference}, booktitle = {32nd International Electric Propulsion Conference}, pages = {1 -- 12}, year = {2011}, abstract = {We investigate the interplanetary flight of a low-thrust space probe to the heliopause,located at a distance of about 200 AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of allistic and electrically propelled flight legs, we have investigated whether the set flight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the first stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol,using Artificial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks' parameter set. Based on a parameter space study, in which the number of thrust units, the unit's specific impulse, and the relative size of the solar power generator were varied, we have chosen one configuration as reference. The transfer time of this reference configuration was 29.6 years and the fastest one, which is technically more challenging, still required 28.3 years. As all flight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher-provided hyperbolic excess energy up to 49 km2/s2. The resulting minimal flight time for the reference configuration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is flexible enough to allow a launch every year. The inclusion of a fly-by at Jupiter finally resulted in a flight time of 23.8 years,which is below the set transfer-time limit. However, compared to the 27.5-year transfer,this mission design has a significantly reduced launch window and mission flexibility if the escape direction is restricted to the heliosphere's "nose".}, language = {en} } @article{OlaruKowalskiSethietal.2012, author = {Olaru, Alexandra Maria and Kowalski, Julia and Sethi, Vaishali and Bl{\"u}mich, Bernhard}, title = {Exchange relaxometry of flow at small P{\´e}clet numbers in a glass bead pack}, series = {Journal of Magnetic Resonance (JMR)}, volume = {220}, journal = {Journal of Magnetic Resonance (JMR)}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1096-0856}, doi = {10.1016/j.jmr.2012.04.015}, pages = {32 -- 44}, year = {2012}, abstract = {In this paper we consider low P{\´e}clet number flow in bead packs. A series of relaxation exchange experiments has been conducted and evaluated by ILT analysis. In the resulting correlation maps, we observed a collapse of the signal and a translation towards smaller relaxation times with increasing flow rates, as well as a signal tilt with respect to the diagonal. In the discussion of the phenomena we present a mathematical theory for relaxation exchange experiments that considers both diffusive and advective transport. We perform simulations based on this theory and discuss them with respect to the conducted experiments.}, language = {en} } @inproceedings{OlaruKowalskiSethietal.2011, author = {Olaru, Alexandra Maria and Kowalski, Julia and Sethi, Vaishali and Bl{\"u}mich, Bernhard}, title = {Fluid Transport in Porous Media probed by Relaxation-Exchange NMR}, series = {2011 Fall Meeting, AGU, San Francisco, Calif., 5-9 Dec.}, booktitle = {2011 Fall Meeting, AGU, San Francisco, Calif., 5-9 Dec.}, year = {2011}, language = {en} } @inproceedings{OttenSchmidWeber2015, author = {Otten, D. and Schmid, M. and Weber, Tobias}, title = {Advances In Sheet Metal-Forming: Reduction Of Tooling Cost By Methodical Optimization}, series = {Proceedings of SAMPE Europe Conference, Amiens , France}, booktitle = {Proceedings of SAMPE Europe Conference, Amiens , France}, year = {2015}, language = {en} } @inproceedings{OttenSchmidtWeber2016, author = {Otten, D. and Schmidt, M. and Weber, Tobias}, title = {Advances in Determination of Material Parameters for Functional Simulations Based on Process Simulations}, series = {SAMPE Europe Conference 16 Liege}, booktitle = {SAMPE Europe Conference 16 Liege}, isbn = {978-1-5108-3800-0}, pages = {570 -- 577}, year = {2016}, language = {en} } @article{OttenWeberArent2018, author = {Otten, Dennis and Weber, Tobias and Arent, Jan-Christoph}, title = {Manufacturing Process Simulation - On Its Way to Industrial Application}, series = {International Journal of Aviation, Aeronautics, and Aerospace}, volume = {5}, journal = {International Journal of Aviation, Aeronautics, and Aerospace}, number = {2}, publisher = {Embry-Riddle Aeronautical University}, address = {Daytona Beach, Fla.}, issn = {2374-6793}, doi = {10.15394/ijaaa.2018.1217}, year = {2018}, abstract = {Manufacturing process simulation (MPS) has become more and more important for aviation and the automobile industry. A highly competitive market requires the use of high performance metals and composite materials in combination with reduced manufacturing cost and time as well as a minimization of the time to market for a new product. However, the use of such materials is expensive and requires sophisticated manufacturing processes. An experience based process and tooling design followed by a lengthy trial-and-error optimization is just not contemporary anymore. Instead, a tooling design process aided by simulation is used more often. This paper provides an overview of the capabilities of MPS in the fields of sheet metal forming and prepreg autoclave manufacturing of composite parts summarizing the resulting benefits for tooling design and manufacturing engineering. The simulation technology is explained briefly in order to show several simplification and optimization techniques for developing industrialized simulation approaches. Small case studies provide examples of an efficient application on an industrial scale.}, language = {en} } @article{OverduinBlomeHoell2007, author = {Overduin, James and Blome, Hans-Joachim and Hoell, Josef}, title = {Wolfgang Priester: from the big bounce to the Lambda-dominated universe}, series = {Naturwissenschaften}, volume = {94}, journal = {Naturwissenschaften}, number = {6}, isbn = {0028-1042}, pages = {417 -- 429}, year = {2007}, language = {en} } @inproceedings{PeekenTroederSchmidtetal.1985, author = {Peeken, Heinz and Troeder, Christoph and Schmidt, J. and Rosenkranz, Josef}, title = {Principles of machine noise reduction}, series = {Inter-noise 85 : proceedings ; 1985 international conference on noise control engineering ; Munich, Sept. 18 - 20, 1985. - (Schriftenreihe der Bundesanstalt f{\"u}r Arbeitsschutz : Tagungsbericht ; 39)}, booktitle = {Inter-noise 85 : proceedings ; 1985 international conference on noise control engineering ; Munich, Sept. 18 - 20, 1985. - (Schriftenreihe der Bundesanstalt f{\"u}r Arbeitsschutz : Tagungsbericht ; 39)}, publisher = {Bundesanstalt f{\"u}r Arbeitsschutz [u.a.]}, address = {Dortmund [u.a.]}, isbn = {3-88314-417-7}, pages = {23 -- 36}, year = {1985}, language = {en} } @inproceedings{PeloniCeriottiDachwald2015, author = {Peloni, A. and Ceriotti, M. and Dachwald, Bernd}, title = {Preliminary trajectory design of a multiple NEO rendezvous mission through solar sailing}, series = {Proceedings of the International Astronautical Congress, IAC, Vol. 8, 2014}, booktitle = {Proceedings of the International Astronautical Congress, IAC, Vol. 8, 2014}, publisher = {Curran}, address = {Red Hook, NY}, isbn = {978-1-63439-986-9}, pages = {5352 -- 5366}, year = {2015}, language = {en} } @article{PeloniCeriottiDachwald2016, author = {Peloni, Alessandro and Ceriotti, Matteo and Dachwald, Bernd}, title = {Solar-sail trajectory design for a multiple near-earth-asteroid rendezvous mission}, series = {Journal of Guidance, Control, and Dynamics}, volume = {39}, journal = {Journal of Guidance, Control, and Dynamics}, number = {12}, publisher = {AIAA}, address = {Reston, Va.}, issn = {0731-5090}, doi = {10.2514/1.G000470}, pages = {2712 -- 2724}, year = {2016}, abstract = {The scientific interest for near-Earth asteroids as well as the interest in potentially hazardous asteroids from the perspective of planetary defense led the space community to focus on near-Earth asteroid mission studies. A multiple near-Earth asteroid rendezvous mission with close-up observations of several objects can help to improve the characterization of these asteroids. This work explores the design of a solar-sail spacecraft for such a mission, focusing on the search of possible sequences of encounters and the trajectory optimization. This is done in two sequential steps: a sequence search by means of a simplified trajectory model and a set of heuristic rules based on astrodynamics, and a subsequent optimization phase. A shape-based approach for solar sailing has been developed and is used for the first phase. The effectiveness of the proposed approach is demonstrated through a fully optimized multiple near-Earth asteroid rendezvous mission. The results show that it is possible to visit five near-Earth asteroids within 10 years with near-term solar-sail technology.}, language = {en} } @article{PeloniDachwaldCeriotti2017, author = {Peloni, Alessandro and Dachwald, Bernd and Ceriotti, Matteo}, title = {Multiple near-earth asteroid rendezvous mission: Solar-sailing options}, series = {Advances in Space Research}, journal = {Advances in Space Research}, number = {In Press, Corrected Proof}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0273-1177}, doi = {10.1016/j.asr.2017.10.017}, year = {2017}, language = {en} } @inproceedings{PeloniDachwaldCeriotti2017, author = {Peloni, Alessandro and Dachwald, Bernd and Ceriotti, Matteo}, title = {Multiple NEA rendezvous mission: Solar sailing options}, series = {Fourth International Symposium on Solar Sailing}, booktitle = {Fourth International Symposium on Solar Sailing}, pages = {1 -- 11}, year = {2017}, abstract = {The scientific interest in near-Earth asteroids (NEAs) and the classification of some of those as potentially hazardous asteroid for the Earth stipulated the interest in NEA exploration. Close-up observations of these objects will increase drastically our knowledge about the overall NEA population. For this reason, a multiple NEA rendezvous mission through solar sailing is investigated, taking advantage of the propellantless nature of this groundbreaking propulsion technology. Considering a spacecraft based on the DLR/ESA Gossamer technology, this work focuses on the search of possible sequences of NEA encounters. The effectiveness of this approach is demonstrated through a number of fully-optimized trajectories. The results show that it is possible to visit five NEAs within 10 years with near-term solar-sail technology. Moreover, a study on a reduced NEA database demonstrates the reliability of the approach used, showing that 58\% of the sequences found with an approximated trajectory model can be converted into real solar-sail trajectories. Lastly, this second study shows the effectiveness of the proposed automatic optimization algorithm, which is able to find solutions for a large number of mission scenarios without any input required from the user.}, language = {en} } @article{PichlerGeorgeSeileretal.2009, author = {Pichler, A. and George, A. and Seiler, F. and Srulijes, J. and Havermann, Marc}, title = {Doppler Picture Velocimetry (DPV) applied to hypersonics}, series = {Shock Waves [Elektronische Ressource] : 26th International Symposium on Shock Waves, Volume 1 / edited by Klaus Hannemann, Friedrich Seiler}, journal = {Shock Waves [Elektronische Ressource] : 26th International Symposium on Shock Waves, Volume 1 / edited by Klaus Hannemann, Friedrich Seiler}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-540-85168-4}, pages = {503 -- 508}, year = {2009}, language = {en} } @inproceedings{PirovanoSeefeldtDachwaldetal.2015, author = {Pirovano, Laura and Seefeldt, Patric and Dachwald, Bernd and Noomen, Ron}, title = {Attitude and Orbital Dynamics Modeling for an Uncontrolled Solar-Sail Experiment in Low-Earth Orbit}, series = {25th International Symposium on Spaceflight Dynamics, 2015, Munich, Germany}, booktitle = {25th International Symposium on Spaceflight Dynamics, 2015, Munich, Germany}, pages = {15 S.}, year = {2015}, language = {en} } @inproceedings{PirovanoSeefeldtDachwaldetal.2015, author = {Pirovano, Laura and Seefeldt, Patric and Dachwald, Bernd and Noomen, Ron}, title = {Attitude and orbital modeling of an uncontrolled solar-sail experiment in low-Earth orbit}, series = {25th International Symposium on Space Flight Dynamics ISSFD}, booktitle = {25th International Symposium on Space Flight Dynamics ISSFD}, pages = {1 -- 15}, year = {2015}, abstract = {Gossamer-1 is the first project of the three-step Gossamer roadmap, the purpose of which is to develop, prove and demonstrate that solar-sail technology is a safe and reliable propulsion technique for long-lasting and high-energy missions. This paper firstly presents the structural analysis performed on the sail to understand its elastic behavior. The results are then used in attitude and orbital simulations. The model considers the main forces and torques that a satellite experiences in low-Earth orbit coupled with the sail deformation. Doing the simulations for varying initial conditions in attitude and rotation rate, the results show initial states to avoid and maximum rotation rates reached for correct and faulty deployment of the sail. Lastly comparisons with the classic flat sail model are carried out to test the hypothesis that the elastic behavior does play a role in the attitude and orbital behavior of the sail}, language = {en} } @inproceedings{PlescherMathiakWillnecker2005, author = {Plescher, Engelbert and Mathiak, Gerhard and Willnecker, Rainer}, title = {Technical aspects of liquid diffusion model experiments}, series = {55th International Astronautical Congress : October 4 - 8, 2004, Vancouver, Canada / International Astronautical Federation. Bd. 8. IAC-04-J.5.04}, booktitle = {55th International Astronautical Congress : October 4 - 8, 2004, Vancouver, Canada / International Astronautical Federation. Bd. 8. IAC-04-J.5.04}, publisher = {International Astronautical Federation}, address = {Paris}, organization = {International Astronautical Congress <55, 2004, Vancouver>}, pages = {5019 -- 5025}, year = {2005}, language = {en} } @inproceedings{QuitterMarinoBauschat2019, author = {Quitter, Julius and Marino, Matthew and Bauschat, J.-Michael}, title = {Highly Non-Planar Aircraft Configurations: Estimation of Flight Mechanical Derivatives Using Low-Order Methods}, series = {Deutscher Luft- und Raumfahrtkongress 2019, DLRK 2019. Darmstadt, Germany}, booktitle = {Deutscher Luft- und Raumfahrtkongress 2019, DLRK 2019. Darmstadt, Germany}, pages = {10 Seiten}, year = {2019}, language = {en} } @article{ReckerBosschaertsWagemakersetal.2010, author = {Recker, Elmar and Bosschaerts, Walter and Wagemakers, Rolf and Hendrick, Patrick and Funke, Harald and B{\"o}rner, Sebastian}, title = {Experimental study of a round jet in cross-flow at low momentum ratio}, series = {15th International Symposium on Applications of Laser Techniques to Fluid Mechanics Lisbon, Portugal, 05-08 July, 2010 - 1}, journal = {15th International Symposium on Applications of Laser Techniques to Fluid Mechanics Lisbon, Portugal, 05-08 July, 2010 - 1}, pages = {1 -- 13}, year = {2010}, language = {en} } @inproceedings{ReimerBraunBallmann2006, author = {Reimer, Lars and Braun, Carsten and Ballmann, Josef}, title = {Analysis of the static and dynamic aero-structural response of an elastic swept wing model by direct aeroelastic simulation}, series = {ICAS 2006 proceedings : 25th Congress of the International Council of the Aeronautical Sciences ; Hamburg, Germany, 3 - 8 September, 2006 : 25th International Congress of Aeronautical Sciences}, booktitle = {ICAS 2006 proceedings : 25th Congress of the International Council of the Aeronautical Sciences ; Hamburg, Germany, 3 - 8 September, 2006 : 25th International Congress of Aeronautical Sciences}, publisher = {Optimage}, address = {Edinburgh}, organization = {International Council of the Aeronautical Sciences (ICAS)}, isbn = {0-9533991-7-6}, pages = {Paper No. 2006-10.3.3}, year = {2006}, language = {en} }