@article{BohnFunkeGier1999, author = {Bohn, D. and Funke, Harald and Gier, J.}, title = {Temperature jet development in a cross-over channel}, series = {Third European Conference on Turbomachinery - fluid dynamics and thermodynamics : : 2 - 5 March 1999, Royal National Hotel, London, UK / organized by the Energy Transfer and Thermofluid Mechanics Group of the Institution of Mechanical Engineers (IMechE); with support and sponsorship from European Commission / Vol. B.}, journal = {Third European Conference on Turbomachinery - fluid dynamics and thermodynamics : : 2 - 5 March 1999, Royal National Hotel, London, UK / organized by the Energy Transfer and Thermofluid Mechanics Group of the Institution of Mechanical Engineers (IMechE); with support and sponsorship from European Commission / Vol. B.}, publisher = {Professional Engineering Publ.}, address = {Bury St. Edmunds}, pages = {671 -- 680}, year = {1999}, language = {en} } @article{BohnFunkeGier1999, author = {Bohn, D. and Funke, Harald and Gier, J.}, title = {Numerical and Experimental Investigations on the Flow in a 4-Stage Turbine with Special Focus on the Development of a Radial Temperature Streak}, series = {ASME Turbo Expo 1999, Indianapolis, USA, 1999}, journal = {ASME Turbo Expo 1999, Indianapolis, USA, 1999}, year = {1999}, language = {en} } @article{BohnFunke2003, author = {Bohn, Dieter and Funke, Harald}, title = {Experimental investigations into the nonuniform flow in a 4-stage turbine with special focus on the flow equalization in the first turbine stage}, series = {ASME TURBO EXPO, Proceedings of the ASME Turbo Expo, 2003}, journal = {ASME TURBO EXPO, Proceedings of the ASME Turbo Expo, 2003}, isbn = {0-7918-3689-4}, pages = {281 -- 289}, year = {2003}, language = {en} } @techreport{BohnFunkeGier1998, author = {Bohn, Dieter and Funke, Harald and Gier, J.}, title = {Untersuchung des Str{\"o}mungsausgleichs in den Schaufelreihen ungleichf{\"o}rmig ungestr{\"o}mter Turbomaschinen}, organization = {Forschungsvereinigung Verbrennungskraftmaschinen (FVV)}, year = {1998}, abstract = {Zwischenbericht {\"u}ber das Vorhaben FVV - Nr. 665 (AIF-Nr. 10780) Heft R 498(1998) S. 123-136. Informationstagung Turbinen, Fr{\"u}hjahr 1998, Frankfurt}, subject = {Str{\"o}mungsmaschine}, language = {de} } @techreport{BohnFunkeGieretal.1999, author = {Bohn, Dieter and Funke, Harald and Gier, J. and Heuer, T.}, title = {Untersuchung des Str{\"o}mungsausgleichs in den Schaufelreihen ungleichf{\"o}rmig ungestr{\"o}mter Turbomaschinen}, organization = {Forschungsvereinigung Verbrennungskraftmaschinen (FVV)}, year = {1999}, abstract = {Abschlussbericht {\"u}ber das Vorhaben FVV-Nr. 665 (AIF-Nr. 10780). Laufzeit 01.08.1996 bis 31.10.1999. Heft R 504 (1999). S. 99-124. Informationstagung Turbinen, Herbst 1999, Heidelberg.}, subject = {Str{\"o}mungsmaschine}, language = {de} } @techreport{BohnFunkeHeuer2001, author = {Bohn, Dieter and Funke, Harald and Heuer, T.}, title = {Sonden-Schaufel-Interaktion bei station{\"a}ren Messungen mit pneumatischen Str{\"o}mungssonden in engen Axialspalten}, organization = {Forschungsvereinigung Verbrennungskraftmaschinen (FVV)}, year = {2001}, abstract = {Abschlussbereicht {\"u}ber das Anschlussvorhaben zu FVV-Nr. 665 (AIF-Nr. 10780). Heft R 511 (2001). 23 S. Informationstagung Turbinen, Fr{\"u}hjahr 2001, Frankfurt.}, subject = {Str{\"o}mungsmaschine}, language = {de} } @article{BohnFunkeHeueretal.2000, author = {Bohn, Dieter and Funke, Harald and Heuer, Tom and B{\"u}tikofer, J.}, title = {Numerical and experimental investigations of the influence of different swirl-ratios on the temperature streak equalization in a 4-stage turbine}, series = {ASME Turbo Expo 2000 ; Munich, May 8-11 2000}, journal = {ASME Turbo Expo 2000 ; Munich, May 8-11 2000}, address = {Munich}, year = {2000}, language = {en} } @techreport{BohnFunkeMetal.2001, author = {Bohn, Dieter and Funke, Harald and M., Wolff. and S{\"u}rken, N.}, title = {Aerodynamische Entlastung der Schaufelspalte durch Konturierung des Meridiankanals [Zwischenbericht]}, organization = {Forschungsvereinigung Verbrennungskraftmaschinen (FVV)}, year = {2001}, abstract = {Zwischenbericht {\"u}ber das Vorhaben Nr. 688 (FVV-Nr. 066880). Laufzeit 01.04.2000 bis 31.03.2001. Heft R 514 (2001). 21 S. Informationstagung Turbinen, Herbst 2001, Dresden-Radebeul}, subject = {Str{\"o}mungsmaschine}, language = {de} } @techreport{BohnFunkeSuerken2000, author = {Bohn, Dieter and Funke, Harald and S{\"u}rken, N.}, title = {Aerodynamische Entlastung der Schaufelspalte durch Konturierung des Meridiankanals [Zwischenbericht]}, organization = {Forschungsvereinigung Verbrennungskraftmaschinen (FVV)}, year = {2000}, abstract = {Zwischenbericht {\"u}ber das Vorhaben FVV-Nr. 0666880. Laufzeit 01.03.1998 bis 31.03.2000. Heft R 507 (2000) . 19 S. Informationstagung Turbinen, Fr{\"u}hjahr 2000, Frankfurt am Main}, subject = {Str{\"o}mungsmaschine}, language = {de} } @article{BohnFunkeSuerkenetal.2001, author = {Bohn, Dieter and Funke, Harald and S{\"u}rken, Norbert and Kreitmeier, F.}, title = {Numerical and experimental investigations on endwall contouring in a four-stage turbine}, series = {ASME Turbo Expo Land Sea \& Air 2001 : June 4 - 8, 2001, New Orleans, Louisiana / IGTI, International Gas Turbine Institute. American Society of Mechanical Engineers. International Gas Turbine Institute ..}, journal = {ASME Turbo Expo Land Sea \& Air 2001 : June 4 - 8, 2001, New Orleans, Louisiana / IGTI, International Gas Turbine Institute. American Society of Mechanical Engineers. International Gas Turbine Institute ..}, publisher = {ASME}, address = {New York, NY}, isbn = {0-7918-3528-6}, pages = {CD-Rom}, year = {2001}, language = {en} } @techreport{BohnFunkeWolffetal.2002, author = {Bohn, Dieter and Funke, Harald and Wolff, M. and S{\"u}rken, N.}, title = {Aerodynamische Entlastung der Schaufelspalte durch Konturierung des Meridiankanals [Abschlussbericht]}, organization = {Forschungsvereinigung Verbrennungskraftmaschinen (FVV)}, year = {2002}, abstract = {Abschlussbericht {\"u}ber das Vorhaben Nr. 688 (FVV-Nr. 066880). Laufzeit 01.04.2000 bis 31.03.2001. Heft R 516 (2002). 24 S. Informationstagung Turbinen, Fr{\"u}hjahr 2002, Frankfurt-M{\"o}hrfelden}, subject = {Str{\"o}mungsmaschine}, language = {de} } @article{BohndickBosseJaenschetal.2021, author = {Bohndick, Carla and Bosse, Elke and J{\"a}nsch, Vanessa K. and Barnat, Miriam}, title = {How different diversity factors affect the perception of first-year requirements in higher education}, series = {Frontline Learning Research}, volume = {9}, journal = {Frontline Learning Research}, number = {2}, publisher = {EARLI}, issn = {2295-3159}, doi = {10.14786/flr.v9i2.667}, pages = {78 -- 95}, year = {2021}, abstract = {In the light of growing university entry rates, higher education institutions not only serve larger numbers of students, but also seek to meet first-year students' ever more diverse needs. Yet to inform universities how to support the transition to higher education, research only offers limited insights. Current studies tend to either focus on the individual factors that affect student success or they highlight students' social background and their educational biography in order to examine the achievement of selected, non-traditional groups of students. Both lines of research appear to lack integration and often fail to take organisational diversity into account, such as different types of higher education institutions or degree programmes. For a more comprehensive understanding of student diversity, the present study includes individual, social and organisational factors. To gain insights into their role for the transition to higher education, we examine how the different factors affect the students' perception of the formal and informal requirements of the first year as more or less difficult to cope with. As the perceived requirements result from both the characteristics of the students and the institutional context, they allow to investigate transition at the interface of the micro and the meso level of higher education. Latent profile analyses revealed that there are no profiles with complex patterns of perception of the first-year requirements, but the identified groups rather differ in the overall level of perceived challenges. Moreover, SEM indicates that the differences in the perception largely depend on the individual factors self-efficacy and volition.}, language = {en} } @incollection{BorggrafeOhndorfDachwaldetal.2012, author = {Borggrafe, Andreas and Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang}, title = {Analysis of interplanetary solar sail trajectories with attitude dynamics}, series = {Dynamics and Control of Space Systems 2012}, booktitle = {Dynamics and Control of Space Systems 2012}, publisher = {Univelt Inc}, address = {San Diego}, isbn = {978-0-87703-587-9}, pages = {1553 -- 1569}, year = {2012}, abstract = {We present a new approach to the problem of optimal control of solar sails for low-thrust trajectory optimization. The objective was to find the required control torque magnitudes in order to steer a solar sail in interplanetary space. A new steering strategy, controlling the solar sail with generic torques applied about the spacecraft body axes, is integrated into the existing low-thrust trajectory optimization software InTrance. This software combines artificial neural networks and evolutionary algorithms to find steering strategies close to the global optimum without an initial guess. Furthermore, we implement a three rotational degree-of-freedom rigid-body attitude dynamics model to represent the solar sail in space. Two interplanetary transfers to Mars and Neptune are chosen to represent typical future solar sail mission scenarios. The results found with the new steering strategy are compared to the existing reference trajectories without attitude dynamics. The resulting control torques required to accomplish the missions are investigated, as they pose the primary requirements to a real on-board attitude control system.}, language = {en} } @inproceedings{BorggraefeDachwald2010, author = {Borggr{\"a}fe, Andreas and Dachwald, Bernd}, title = {Mission performance evaluation for solar sails using a refined SRP force model with variable optical coefficients}, series = {2nd International Symposium on Solar Sailing}, booktitle = {2nd International Symposium on Solar Sailing}, pages = {1 -- 6}, year = {2010}, abstract = {Solar sails provide ignificant advantages over other low-thrust propulsion systems because they produce thrust by the momentum exchange from solar radiation pressure (SRP) and thus do not consume any propellant.The force exerted on a very thin sail foil basically depends on the light incidence angle. Several analytical SRP force models that describe the SRP force acting on the sail have been established since the 1970s. All the widely used models use constant optical force coefficients of the reflecting sail material. In 2006,MENGALI et al. proposed a refined SRP force model that takes into account the dependancy of the force coefficients on the light incident angle,the sail's distance from the sun (and thus the sail emperature) and the surface roughness of the sail material [1]. In this paper, the refined SRP force model is compared to the previous ones in order to identify the potential impact of the new model on the predicted capabilities of solar sails in performing low-cost interplanetary space missions. All force models have been implemented within InTrance, a global low-thrust trajectory optimization software utilizing evolutionary neurocontrol [2]. Two interplanetary rendezvous missions, to Mercury and the near-Earth asteroid 1996FG3, are investigated. Two solar sail performances in terms of characteristic acceleration are examined for both scenarios, 0.2 mm/s2 and 0.5 mm/s2, termed "low" and "medium" sail performance. In case of the refined SRP model, three different values of surface roughness are chosen, h = 0 nm, 10 nm and 25 nm. The results show that the refined SRP force model yields shorter transfer times than the standard model.}, language = {en} } @incollection{BosseBarnat2019, author = {Bosse, Elke and Barnat, Miriam}, title = {Kombination quantitativer und qualitativer Methoden zur Untersuchung der Studieneingangsphase}, series = {Hochschulbildungsforschung. Theoretische, methodologische und methodische Denkanst{\"o}ße f{\"u}r die Hochschuldidaktik}, booktitle = {Hochschulbildungsforschung. Theoretische, methodologische und methodische Denkanst{\"o}ße f{\"u}r die Hochschuldidaktik}, editor = {Jenert, Tobias and Reinmann, Gabi and Schmohl, Tobias}, publisher = {Springer VS}, address = {Wiesbaden}, isbn = {978-3-658-20308-5}, pages = {169 -- 184}, year = {2019}, language = {de} } @incollection{BrandtGueskenBuechenetal.1997, author = {Brandt, D. and G{\"u}sken, J. and B{\"u}chen, W. and [u.a.], and Wahle, Michael}, title = {Konstruieren mit Aluminium [Kapitel 4]}, series = {Aluminium-Taschenbuch / Hrsg.: Aluminium-Zentrale D{\"u}sseldorf. - Bd. 3: Weiterverarbeitung und Anwendung}, booktitle = {Aluminium-Taschenbuch / Hrsg.: Aluminium-Zentrale D{\"u}sseldorf. - Bd. 3: Weiterverarbeitung und Anwendung}, edition = {15. Auflage}, publisher = {Aluminium-Verlag}, address = {D{\"u}sseldorf}, isbn = {3-87017-243-6}, pages = {359 -- 544}, year = {1997}, language = {de} } @book{Braun2007, author = {Braun, Carsten}, title = {Ein modulares Verfahren f{\"u}r die numerische aeroelastische Analyse von Luftfahrzeugen}, pages = {VI, 199 S.}, year = {2007}, abstract = {Aachen, Techn. Hochschule, Diss., 2007}, language = {de} } @inproceedings{BraunBouckeBallmann2005, author = {Braun, Carsten and Boucke, Alexander and Ballmann, Josef}, title = {Numerical prediction of the wing deformation of a high speed transport aircraft type wind tunnel model by direct aeroelastic simulation}, series = {Conference proceedings : CEAS/AIAA/DGLR International Forum on Aeroelasticity and Structural Dynamics IFASD 2005 : M{\"u}nchen, June 28 - July 1, 2005. DGLR-Bericht. 2005,04}, booktitle = {Conference proceedings : CEAS/AIAA/DGLR International Forum on Aeroelasticity and Structural Dynamics IFASD 2005 : M{\"u}nchen, June 28 - July 1, 2005. DGLR-Bericht. 2005,04}, publisher = {DGLR}, address = {Bonn}, isbn = {3-932182-43-X}, pages = {1 CD-ROM}, year = {2005}, language = {en} } @incollection{BraunBouckeBallmann2005, author = {Braun, Carsten and Boucke, Alexander and Ballmann, Josef}, title = {Numerical study of the influence of dynamic pressure and deflected ailerons on the deformation of a high speed wing model}, series = {High performance computing in science and engineering '04. Transactions of the High Performance Computing Center Stuttgart (HLRS) 2004 / Eds.: Egon Krause ...}, booktitle = {High performance computing in science and engineering '04. Transactions of the High Performance Computing Center Stuttgart (HLRS) 2004 / Eds.: Egon Krause ...}, publisher = {Springer}, address = {Berlin}, isbn = {3-540-22943-4}, pages = {225 -- 236}, year = {2005}, language = {en} } @incollection{BraunBouckeHankeetal.2003, author = {Braun, Carsten and Boucke, Alexander and Hanke, M. and Karavas, Alexandros and Ballmann, Josef}, title = {Prediction of the model deformation of a high speed transport aircraft type wing by direct aeroelastic simulation}, series = {High performance computing in science and engineering '03. Transactions of the High Performance Computing Center Stuttgart (HLRS) 2003 / Eds.: Egon Krause ...}, booktitle = {High performance computing in science and engineering '03. Transactions of the High Performance Computing Center Stuttgart (HLRS) 2003 / Eds.: Egon Krause ...}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-540-40850-5}, pages = {331 -- 342}, year = {2003}, language = {de} } @article{BreitschuhGraberHagemannetal.2003, author = {Breitschuh, S. and Graber, S. and Hagemann, Hans-J{\"u}rgen and Hemdt, A. vom and Schmitz, G{\"u}nter}, title = {Telematiklabore mit LabVIEW in der Ingenieurausbildung}, series = {Virtuelle Instrumente in der Praxis : Messtechnik, Automatisierung ; Begleitband zum Kongress VIP 2003 / Rahman Jamal ; Hans Jaschinski (Hrsg.).}, journal = {Virtuelle Instrumente in der Praxis : Messtechnik, Automatisierung ; Begleitband zum Kongress VIP 2003 / Rahman Jamal ; Hans Jaschinski (Hrsg.).}, publisher = {H{\"u}thig}, address = {Heidelberg [u.a.]}, isbn = {3-7785-2908-0}, pages = {458 -- 464}, year = {2003}, language = {de} } @incollection{BrittenBraunHesseetal.2003, author = {Britten, G. and Braun, Carsten and Hesse, M. and Ballmann, Josef}, title = {Computational aeroelasticity with reduced structural models}, series = {Flow modulation and fluid-structure interaction at airplane wings : research results of the Collaborative Research Center SFB 401 at RWTH Aachen, University of Technology, Aachen, Germany / Josef Ballmann (Ed.) Notes on numerical fluid mechanics and multidisciplinary design. Vol. 84}, booktitle = {Flow modulation and fluid-structure interaction at airplane wings : research results of the Collaborative Research Center SFB 401 at RWTH Aachen, University of Technology, Aachen, Germany / Josef Ballmann (Ed.) Notes on numerical fluid mechanics and multidisciplinary design. Vol. 84}, publisher = {Springer}, address = {Berlin}, isbn = {3-540-40209-8}, pages = {275 -- 299}, year = {2003}, language = {en} } @book{Bullerschen1987, author = {Bullerschen, Klaus-Gerd}, title = {Theoretische Untersuchungen zur thermischen Belastung der Elektroden des Lichtbogenofens und deren K{\"u}hlung durch Heat Pipes}, publisher = {Techn. Hochsch., Fak. f{\"u}r Bergbau, H{\"u}ttenwesen u. Geowiss.}, address = {Aachen}, pages = {121 S. : graph. Darst., 21 cm}, year = {1987}, language = {de} } @article{Bullerschen1990, author = {Bullerschen, Klaus-Gerd}, title = {Rechenmodelle zur Stromverdr{\"a}ngung in ein- und mehrphasigen elektrischen Leitungen komplexer Geometrie}, series = {Elektrow{\"a}rme International, Edition B (Industrielle Elektrow{\"a}rme). 48 (1990), H. 4}, journal = {Elektrow{\"a}rme International, Edition B (Industrielle Elektrow{\"a}rme). 48 (1990), H. 4}, isbn = {0340-3521}, pages = {199 -- 210}, year = {1990}, language = {de} } @article{Bullerschen1989, author = {Bullerschen, Klaus-Gerd}, title = {Hochtemperaturtechnik. Interne Arbeitssitzung des GVC-Fachausschusses 'Hochtemperaturtechnik'}, series = {Chemie Ingenieur Technik. 61 (1989), H. 6}, journal = {Chemie Ingenieur Technik. 61 (1989), H. 6}, isbn = {0009-286X}, pages = {510 -- 512}, year = {1989}, language = {de} } @article{BullerschenLeonard1990, author = {Bullerschen, Klaus-Gerd and L{\´e}onard, G.}, title = {Hochtemperaturtechnik}, series = {Chemie Ingenieur Technik. 62 (1990), H. 3}, journal = {Chemie Ingenieur Technik. 62 (1990), H. 3}, isbn = {0009-286X}, pages = {252 -- 256}, year = {1990}, language = {de} } @article{BullerschenVoigtFriedrich1990, author = {Bullerschen, Klaus-Gerd and Voigt, H. and Friedrich, R.}, title = {Experimentelle und mathematische Untersuchungen zum Heißtransport von Stranggußbrammen}, series = {Stahl und Eisen. 110 (1990), H. 6}, journal = {Stahl und Eisen. 110 (1990), H. 6}, isbn = {0378-7559}, pages = {97 -- 105}, year = {1990}, language = {de} } @article{BullerschenWilhelmi1990, author = {Bullerschen, Klaus-Gerd and Wilhelmi, Herbert}, title = {K{\"u}hlung von Lichtbogenofenelektroden durch W{\"a}rmerohre}, series = {Stahl und Eisen. 110 (1990), H. 8}, journal = {Stahl und Eisen. 110 (1990), H. 8}, isbn = {0378-7559}, pages = {91 -- 98}, year = {1990}, language = {de} } @article{BullerschenWilhelmi1991, author = {Bullerschen, Klaus-Gerd and Wilhelmi, Herbert}, title = {Cooling of arc furnace electrodes with heat pipes}, series = {Chemical Engineering \& Technology. 14 (1991), H. 1}, journal = {Chemical Engineering \& Technology. 14 (1991), H. 1}, isbn = {0930-7516}, pages = {45 -- 53}, year = {1991}, language = {en} } @article{BullerschenWilhelmiWimmer1985, author = {Bullerschen, Klaus-Gerd and Wilhelmi, Herbert and Wimmer, W.}, title = {Influence of non-uniform material properties and water cooling on current density and temperature profiles in arc furnace elektrodes}, series = {Steel Research. 56 (1985), H. 11}, journal = {Steel Research. 56 (1985), H. 11}, isbn = {0177-4832}, pages = {559 -- 564}, year = {1985}, language = {en} } @misc{BurlageHoeraufKlandtetal.1998, author = {Burlage, Thomas and H{\"o}rauf, Martin and Klandt, Michael and Wahle, Michael}, title = {Schwingungsd{\"a}mpfer : Offenlegungsschrift}, publisher = {Deutsches Patent- und Markenamt / Europ{\"a}isches Patentamt}, address = {M{\"u}nchen / Den Hague}, pages = {14 S. : graph. Darst.}, year = {1998}, language = {de} } @incollection{BusseEschMuntaniol2015, author = {Busse, Daniel and Esch, Thomas and Muntaniol, Roman}, title = {Thermal management in E-carsharing vehicles - preconditioning concepts of passenger compartments}, series = {E-Mobility in Europe : trends and good practice}, booktitle = {E-Mobility in Europe : trends and good practice}, publisher = {Springer}, address = {Cham [u.a.]}, isbn = {978-3-319-13193-1}, doi = {10.1007/978-3-319-13194-8_18}, pages = {327 -- 343}, year = {2015}, abstract = {The issue of thermal management in electric vehicles includes the topics of drivetrain cooling and heating, interior temperature, vehicle body conditioning and safety. In addition to the need to ensure optimal thermal operating conditions of the drivetrain components (drive motor, battery and electrical components), thermal comfort must be provided for the passengers. Thermal comfort is defined as the feeling which expresses the satisfaction of the passengers with the ambient conditions in the compartment. The influencing factors on thermal comfort are the temperature and humidity as well as the speed of the indoor air and the clothing and the activity of the passengers, in addition to the thermal radiation and the temperatures of the interior surfaces. The generation and the maintenance of free visibility (ice- and moisture-free windows) count just as important as on-demand heating and cooling of the entire vehicle. A Carsharing climate concept of the innovative ec2go vehicle stipulates and allows for only seating areas used by passengers to be thermally conditioned in a close-to-body manner. To enable this, a particular feature has been added to the preconditioning of the Carsharing electric vehicle during the electric charging phase at the parking station.}, language = {en} } @article{BecretGrossenTrillaetal.2007, author = {B{\´e}cret, P. and Grossen, J. and Trilla, J. and Robinson, A. and Bosschaerts, W. and Funke, Harald and Hendrick, P.}, title = {Testing and numerical study of a 10 kW hydrogen micro combustor}, series = {International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications <7, 2007, Freiburg, Breisgau> ; PowerMEMS ; 7}, journal = {International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications <7, 2007, Freiburg, Breisgau> ; PowerMEMS ; 7}, pages = {367 -- 370}, year = {2007}, language = {en} } @article{BoehnischBraunMuscarelloetal.2024, author = {B{\"o}hnisch, Nils and Braun, Carsten and Muscarello, Vincenzo and Marzocca, Pier}, title = {About the wing and whirl flutter of a slender wing-propeller system}, series = {Journal of Aircraft}, journal = {Journal of Aircraft}, publisher = {American Institute of Aeronautics and Astronautics}, issn = {1533-3868}, doi = {10.2514/1.C037542}, pages = {1 -- 14}, year = {2024}, abstract = {Next-generation aircraft designs often incorporate multiple large propellers attached along the wingspan (distributed electric propulsion), leading to highly flexible dynamic systems that can exhibit aeroelastic instabilities. This paper introduces a validated methodology to investigate the aeroelastic instabilities of wing-propeller systems and to understand the dynamic mechanism leading to wing and whirl flutter and transition from one to the other. Factors such as nacelle positions along the wing span and chord and its propulsion system mounting stiffness are considered. Additionally, preliminary design guidelines are proposed for flutter-free wing-propeller systems applicable to novel aircraft designs. The study demonstrates how the critical speed of the wing-propeller systems is influenced by the mounting stiffness and propeller position. Weak mounting stiffnesses result in whirl flutter, while hard mounting stiffnesses lead to wing flutter. For the latter, the position of the propeller along the wing span may change the wing mode shapes and thus the flutter mechanism. Propeller positions closer to the wing tip enhance stability, but pusher configurations are more critical due to the mass distribution behind the elastic axis.}, language = {en} } @article{BoehnischBraunMuscarelloetal.2023, author = {B{\"o}hnisch, Nils and Braun, Carsten and Muscarello, Vincenzo and Marzocca, Pier}, title = {A sensitivity study on aeroelastic instabilities of slender wings with a large propeller}, series = {AIAA SCITECH 2023 Forum}, journal = {AIAA SCITECH 2023 Forum}, publisher = {AIAA}, doi = {10.2514/6.2023-1893}, pages = {1 -- 14}, year = {2023}, abstract = {Next-generation aircraft designs often incorporate multiple large propellers attached along the wingspan. These highly flexible dynamic systems can exhibit uncommon aeroelastic instabilities, which should be carefully investigated to ensure safe operation. The interaction between the propeller and the wing is of particular importance. It is known that whirl flutter is stabilized by wing motion and wing aerodynamics. This paper investigates the effect of a propeller onto wing flutter as a function of span position and mounting stiffness between the propeller and wing. The analysis of a comparison between a tractor and pusher configuration has shown that the coupled system is more stable than the standalone wing for propeller positions near the wing tip for both configurations. The wing fluttermechanism is mostly affected by the mass of the propeller and the resulting change in eigenfrequencies of the wing. For very weak mounting stiffnesses, whirl flutter occurs, which was shown to be stabilized compared to a standalone propeller due to wing motion. On the other hand, the pusher configuration is, as to be expected, the more critical configuration due to the attached mass behind the elastic axis.}, language = {de} } @phdthesis{Boerner2013, author = {B{\"o}rner, Sebastian}, title = {Optimization and testing of a low NOx hydrogen fuelled gas turbine}, publisher = {Universit{\´e} Libre de Bruxelles}, address = {Bruxelles}, pages = {XVI, 144 S.}, year = {2013}, language = {en} } @article{BoernerFunkeHendricketal.2010, author = {B{\"o}rner, Sebastian and Funke, Harald and Hendrick, P. and Recker, E.}, title = {Control system modifications for a hydrogen fuelled gas-turbine}, series = {ISROMAC 13, 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Honolulu, HI, US, Apr 4-7, 2010}, journal = {ISROMAC 13, 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Honolulu, HI, US, Apr 4-7, 2010}, publisher = {Curran}, address = {Red Hook, NY}, isbn = {978-1-617-38848-4}, pages = {665 -- 670}, year = {2010}, language = {en} } @inproceedings{BoernerFunkeHendricketal.2009, author = {B{\"o}rner, Sebastian and Funke, Harald and Hendrick, P. and Recker, E.}, title = {LES of Jets In Cross-Flow and Application to the "Micromix" Hydrogen Combustion}, series = {XIX International Symposium on Air Breathing Engines 2009 (ISABE 2009) : Proceedings of a meeting held 7-11 September 2009, Montreal, Canada}, booktitle = {XIX International Symposium on Air Breathing Engines 2009 (ISABE 2009) : Proceedings of a meeting held 7-11 September 2009, Montreal, Canada}, isbn = {9781615676064}, pages = {1555 -- 1561}, year = {2009}, language = {en} } @article{BuehlerChristenKowalskietal.2011, author = {B{\"u}hler, Yves and Christen, Marc and Kowalski, Julia and Bartelt, Perry}, title = {Sensitivity of snow avalanche simulations to digital elevation model quality and resolution}, series = {Annals of Glaciology}, volume = {52}, journal = {Annals of Glaciology}, number = {58}, publisher = {Cambridge University Press}, address = {Cambridge}, isbn = {1727-5644}, pages = {72 -- 80}, year = {2011}, abstract = {Digital elevation models (DEMs), represent the three-dimensional terrain and are the basic input for numerical snow avalanche dynamics simulations. DEMs can be acquired using topographic maps or remote-sensing technologies, such as photogrammetry or lidar. Depending on the acquisition technique, different spatial resolutions and qualities are achieved. However, there is a lack of studies that investigate the sensitivity of snow avalanche simulation algorithms to the quality and resolution of DEMs. Here, we perform calculations using the numerical avalance dynamics model RAMMS, varying the quality and spatial resolution of the underlying DEMs, while holding the simulation parameters constant. We study both channelized and open-terrain avalanche tracks with variable roughness. To quantify the variance of these simulations, we use well-documented large-scale avalanche events from Davos, Switzerland (winter 2007/08), and from our large-scale avalanche test site, Valĺee de la Sionne (winter 2005/06). We find that the DEM resolution and quality is critical for modeled flow paths, run-out distances, deposits, velocities and impact pressures. Although a spatial resolution of ~25 m is sufficient for large-scale avalanche modeling, the DEM datasets must be checked carefully for anomalies and artifacts before using them for dynamics calculations.}, language = {en} } @inproceedings{BuehrigPolaczekRoethBaumeisteretal.2006, author = {B{\"u}hrig-Polaczek, Andreas and R{\"o}th, Thilo and Baumeister, E. and Nowack, N. and S{\"u}ßmann, Torsten}, title = {Hybride Leichtbaustrukturen in Stahlblech-Leichtmetall Verbundguss}, year = {2006}, abstract = {Stahl-Leichtmetall-Hybride mit hohen Leistungspotentialen k{\"o}nnen heute wirtschaftlich abgebildet werden und eignen sich m{\"o}glicherweise auch zum Einsatz in Fahrzeugkarosserien}, subject = {Karosseriebau}, language = {de} } @article{CampenKowalskiLyonsetal.2019, author = {Campen, R. and Kowalski, Julia and Lyons, W.B. and Tulaczyk, S. and Dachwald, Bernd and Pettit, E. and Welch, K. A. and Mikucki, J.A.}, title = {Microbial diversity of an Antarctic subglacial community and high-resolution replicate sampling inform hydrological connectivity in a polar desert}, series = {Environmental Microbiology}, journal = {Environmental Microbiology}, number = {accepted article}, publisher = {Wiley}, address = {Weinheim}, issn = {1462-2920}, doi = {10.1111/1462-2920.14607}, year = {2019}, language = {en} } @inproceedings{CarzanaDachwaldNoomen2017, author = {Carzana, Livio and Dachwald, Bernd and Noomen, Ron}, title = {Model and trajectory optimization for an ideal laser-enhanced solar sail}, series = {68th International Astronautical Congress}, booktitle = {68th International Astronautical Congress}, year = {2017}, abstract = {A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The potential source of the laser beam is a laser satellite that coverts solar power (in the inner solar system) or nuclear power (in the outer solar system) into laser power. Such a laser satellite (or many of them) can orbit anywhere in the solar system and its optimal orbit (or their optimal orbits) for a given mission is a subject for future research. This contribution provides the model for an ideal laser-enhanced solar sail and investigates how a laser can enhance the thrusting capability of such a sail. The term "ideal" means that the solar sail is assumed to be perfectly reflecting and that the laser beam is assumed to have a constant areal power density over the whole sail area. Since a laser beam has a limited divergence, it can provide radiation pressure at much larger solar distances and increase the radiation pressure force into the desired direction. Therefore, laser-enhanced solar sails may make missions feasible, that would otherwise have prohibitively long flight times, e.g. rendezvous missions in the outer solar system. This contribution will also analyze exemplary mission scenarios and present optimial trajectories without laying too much emphasis on the design and operations of the laser satellites. If the mission studies conclude that laser-enhanced solar sails would have advantages with respect to "traditional" solar sails, a detailed study of the laser satellites and the whole system architecture would be the second next step}, language = {en} } @article{ChristenBarteltKowalski2010, author = {Christen, Marc and Bartelt, Perry and Kowalski, Julia}, title = {Back calculation of the In den Arelen avalanche with RAMMS: Interpretation of model results}, series = {Annals of Glaciology}, volume = {51}, journal = {Annals of Glaciology}, number = {54}, publisher = {Cambridge University Press}, address = {Cambridge}, isbn = {1727-5644}, doi = {10.3189/172756410791386553}, pages = {161 -- 168}, year = {2010}, abstract = {Two- and three-dimensional avalanche dynamics models are being increasingly used in hazard-mitigation studies. These models can provide improved and more accurate results for hazard mapping than the simple one-dimensional models presently used in practice. However, two- and three-dimensional models generate an extensive amount of output data, making the interpretation of simulation results more difficult. To perform a simulation in three-dimensional terrain, numerical models require a digital elevation model, specification of avalanche release areas (spatial extent and volume), selection of solution methods, finding an adequate calculation resolution and, finally, the choice of friction parameters. In this paper, the importance and difficulty of correctly setting up and analysing the results of a numerical avalanche dynamics simulation is discussed. We apply the two-dimensional simulation program RAMMS to the 1968 extreme avalanche event In den Arelen. We show the effect of model input variations on simulation results and the dangers and complexities in their interpretation.}, language = {en} } @inproceedings{ChristenBarteltKowalskietal.2008, author = {Christen, Marc and Bartelt, Perry and Kowalski, Julia and Stoffel, Lukus}, title = {Calculation of dense snow avalanches in three-dimensional terrain with the numerical simulation programm RAMMS}, series = {Proceedings ISSW 2008 ; International Snow Science Workshop. Whistler 2008}, booktitle = {Proceedings ISSW 2008 ; International Snow Science Workshop. Whistler 2008}, pages = {709 -- 716}, year = {2008}, abstract = {Numerical models have become an essential part of snow avalanche engineering. Recent advances in understanding the rheology of flowing snow and the mechanics of entrainment and deposition have made numerical models more reliable. Coupled with field observations and historical records, they are especially helpful in understanding avalanche flow in complex terrain. However, the application of numerical models poses several new challenges to avalanche engineers. A detailed understanding of the avalanche phenomena is required to specify initial conditions (release zone dimensions and snowcover entrainment rates) as well as the friction parameters, which are no longer based on empirical back-calculations, rather terrain roughness, vegetation and snow properties. In this paper we discuss these problems by presenting the computer model RAMMS, which was specially designed by the SLF as a practical tool for avalanche engineers. RAMMS solves the depth-averaged equations governing avalanche flow with first and second-order numerical solution schemes. A tremendous effort has been invested in the implementation of advanced input and output features. Simulation results are therefore clearly and easily visualized to simplify their interpretation. More importantly, RAMMS has been applied to a series of well-documented avalanches to gauge model performance. In this paper we present the governing differential equations, highlight some of the input and output features of RAMMS and then discuss the simulation of the Gatschiefer avalanche that occurred in April 2008, near Klosters/Monbiel, Switzerland.}, language = {en} } @article{ChristenKowalskiBartelt2010, author = {Christen, Marc and Kowalski, Julia and Bartelt, Perry}, title = {RAMMS: Numerical simulation of dense snow avalanches in three-dimensional terrain}, series = {Cold Regions Science and Technology}, volume = {63}, journal = {Cold Regions Science and Technology}, number = {1-2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-7441}, doi = {10.1016/j.coldregions.2010.04.005}, pages = {1 -- 14}, year = {2010}, abstract = {Numerical avalanche dynamics models have become an essential part of snow engineering. Coupled with field observations and historical records, they are especially helpful in understanding avalanche flow in complex terrain. However, their application poses several new challenges to avalanche engineers. A detailed understanding of the avalanche phenomena is required to construct hazard scenarios which involve the careful specification of initial conditions (release zone location and dimensions) and definition of appropriate friction parameters. The interpretation of simulation results requires an understanding of the numerical solution schemes and easy to use visualization tools. We discuss these problems by presenting the computer model RAMMS, which was specially designed by the SLF as a practical tool for avalanche engineers. RAMMS solves the depth-averaged equations governing avalanche flow with accurate second-order numerical solution schemes. The model allows the specification of multiple release zones in three-dimensional terrain. Snow cover entrainment is considered. Furthermore, two different flow rheologies can be applied: the standard Voellmy-Salm (VS) approach or a random kinetic energy (RKE) model, which accounts for the random motion and inelastic interaction between snow granules. We present the governing differential equations, highlight some of the input and output features of RAMMS and then apply the models with entrainment to simulate two well-documented avalanche events recorded at the Vall{\´e}e de la Sionne test site.}, language = {en} } @book{Cordewiner1982, author = {Cordewiner, Hans-Josef}, title = {Einsatz und Entwicklung der Datenverarbeitung im Bereich der Konstruktion}, publisher = {Zentralbibliothek d. Kernforschungsanlage}, address = {J{\"u}lich}, pages = {I, 31 S. : Ill., graph. Darst.}, year = {1982}, language = {de} } @book{Cordewiner1979, author = {Cordewiner, Hans-Josef}, title = {Numerische Berechnung des Tritium-Verhaltens von Kugelhaufenreaktoren am Beispiel des AVR-Reaktors}, publisher = {Zentralbibliothek d. Kernforschungsanlage J{\"u}lich GmbH}, address = {J{\"u}lich}, pages = {96, 19 S. : 16 graph. Darst.}, year = {1979}, language = {de} } @book{Cordewiner1983, author = {Cordewiner, Hans-Josef}, title = {Fertigung und Test der Metallfaltbelaege des TEXTOR-Vakuumgefaesses}, publisher = {Kernforschungsanlage Juelich GmbH}, address = {J{\"u}lich}, year = {1983}, language = {de} } @book{CordewinerSchoernerKochetal.1983, author = {Cordewiner, Hans-Josef and Schoerner, M. and Koch, R. and Bachner, E.}, title = {Untersuchungen zum Einsatz eines CAD-Systems fuer den Konstruktionsbereich der Zentralabteilung Allgemeine Technologie der Kernforschungsanlage Juelich}, publisher = {Gesellschaft fuer Elektronische Informationsverarbeitung}, address = {Aachen}, year = {1983}, language = {de} } @inproceedings{Czupalla2017, author = {Czupalla, Markus}, title = {Pflanzen oder Maschinen - was l{\"a}ßt uns auf dem Mars {\"u}berleben?}, series = {{\"U}berleben im Weltraum. Auf dem Weg zu neuen Grenzen. 21. Berliner Kolloquium der Daimler und Benz Stiftung 24. Mai 2017}, booktitle = {{\"U}berleben im Weltraum. Auf dem Weg zu neuen Grenzen. 21. Berliner Kolloquium der Daimler und Benz Stiftung 24. Mai 2017}, pages = {12 -- 12}, year = {2017}, language = {de} }