TY - JOUR A1 - Franke, Thomas A1 - Bosis, R. A1 - Napoli, M.-D. T1 - Über das Internet steuerbarer Gebläseprüfstand mit einstellbaren Eintrittsleitschaufeln JF - Virtuelle Instrumente in der Praxis : Begleitband zum Kongreß VIP 2001 / Rahman Jamal ; Hans Jaschinski Y1 - 2001 SN - 3-7785-2829-7 N1 - Serie Praxiswissen Elektronik-Industrie : Messtechnik SP - 219 EP - 225 PB - Hüthig Verlag CY - Heidelberg [u.a.] ER - TY - JOUR A1 - Fornaciari, Andrea A1 - Guidetti, Marco A1 - Havermann, Marc A1 - Lettini, Antonio T1 - Maccine mobili più efficienti JF - Fluidotecnica N2 - Secondo le attuali normative tutte le macchine mobili, entro il 2012, dovranno essere soggette a un incremento di efficienza energetica. Un’evoluzione del sistema idraulico potrà contribuire in maniera significativa al miglioramento richiesto. Elettronica e idraulica sempre più protagoniste. Y1 - 2010 IS - 345 SP - 11 EP - 14 PB - Quine Business Publisher CY - Milano ER - TY - JOUR A1 - Fischer, Jan-Thomas A1 - Kowalski, Julia A1 - Pudasaini, Shiva P. A1 - Miller, S. A. T1 - Dynamic Avalanche Modeling in Natural Terrain JF - International Snow Science Workshop, Davos 2009, Proceedings ; Proc. ISSW 2009 N2 - The powerful avalanche simulation toolbox RAMMS (Rapid Mass Movements) is based on a depth-averaged hydrodynamic system of equations with a Voellmy-Salm friction relation. The two empirical friction parameters μ and � correspond to a dry Coulomb friction and a viscous resistance, respectively. Although μ and � lack a proper physical explanation, 60 years of acquired avalanche data in the Swiss Alps made a systematic calibration possible. RAMMS can therefore successfully model avalanche flow depth, velocities, impact pressure and run out distances. Pudasaini and Hutter (2003) have proposed extended, rigorously derived model equations that account for local curvature and twist. A coordinate transformation into a reference system, applied to the actual mountain topography of the natural avalanche path, is performed. The local curvature and the twist of the avalanche path induce an additional term in the overburden pressure. This leads to a modification of the Coulomb friction, the free-surface pressure gradient, the pressure induced by the channel, and the gravity components along and normal to the curved and twisted reference surface. This eventually guides the flow dynamics and deposits of avalanches. In the present study, we investigate the influence of curvature on avalanche flow in real mountain terrain. Simulations of real avalanche paths are performed and compared for the different models approaches. An algorithm to calculate curvature in real terrain is introduced in RAMMS. This leads to a curvature dependent friction relation in an extended version of the Voellmy-Salm model equations. Our analysis provides yet another step in interpreting the physical meaning and significance of the friction parameters used in the RAMMS computational environment. KW - snow KW - avalanche Y1 - 2009 SP - 448 EP - 452 ER - TY - JOUR A1 - Fischer, Jan-Thomas A1 - Kowalski, Julia A1 - Pudasaini, Shiva P. T1 - Topographic curvature effects in applied avalanche modelling JF - Cold Regions Science and Technology N2 - This paper describes the implementation of topographic curvature effects within the RApid Mass MovementS (RAMMS) snow avalanche simulation toolbox. RAMMS is based on a model similar to shallow water equations with a Coulomb friction relation and the velocity dependent Voellmy drag. It is used for snow avalanche risk assessment in Switzerland. The snow avalanche simulation relies on back calculation of observed avalanches. The calibration of the friction parameters depends on characteristics of the avalanche track. The topographic curvature terms are not yet included in the above mentioned classical model. Here, we fundamentally improve this model by mathematically and physically including the topographic curvature effects. By decomposing the velocity dependent friction into a topography dependent term that accounts for a curvature enhancement in the Coulomb friction, and a topography independent contribution similar to the classical Voellmy drag, we construct a general curvature dependent frictional resistance, and thus propose new extended model equations. With three site-specific examples, we compare the apparent frictional resistance of the new approach, which includes topographic curvature effects, to the classical one. Our simulation results demonstrate substantial effects of the curvature on the flow dynamics e.g., the dynamic pressure distribution along the slope. The comparison of resistance coefficients between the two models demonstrates that the physically based extension presents an improvement to the classical approach. Furthermore a practical example highlights its influence on the pressure outline in the run out zone of the avalanche. Snow avalanche dynamics modeling natural terrain curvature centrifugal force friction coefficients. KW - Snow KW - Avalanche Y1 - 2012 U6 - https://doi.org/10.1016/j.coldregions.2012.01.005 SN - 1872-7441 VL - 74-75 SP - 21 EP - 30 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Finger, Felix A1 - Götten, Falk A1 - Braun, Carsten A1 - Bil, Cees T1 - Mass, primary energy, and cost: the impact of optimization objectives on the initial sizing of hybrid-electric general aviation aircraft JF - CEAS Aeronautical Journal N2 - For short take-off and landing (STOL) aircraft, a parallel hybrid-electric propulsion system potentially offers superior performance compared to a conventional propulsion system, because the short-take-off power requirement is much higher than the cruise power requirement. This power-matching problem can be solved with a balanced hybrid propulsion system. However, there is a trade-off between wing loading, power loading, the level of hybridization, as well as range and take-off distance. An optimization method can vary design variables in such a way that a minimum of a particular objective is attained. In this paper, a comparison between the optimization results for minimum mass, minimum consumed primary energy, and minimum cost is conducted. A new initial sizing algorithm for general aviation aircraft with hybrid-electric propulsion systems is applied. This initial sizing methodology covers point performance, mission performance analysis, the weight estimation process, and cost estimation. The methodology is applied to the design of a STOL general aviation aircraft, intended for on-demand air mobility operations. The aircraft is sized to carry eight passengers over a distance of 500 km, while able to take off and land from short airstrips. Results indicate that parallel hybrid-electric propulsion systems must be considered for future STOL aircraft. Y1 - 2020 U6 - https://doi.org/10.1007/s13272-020-00449-8 SN - 1869-5590 N1 - Corresponding author: Felix Finger VL - 2020 IS - 11 SP - 713 EP - 730 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Finger, Felix A1 - Götten, Falk T1 - Neue Ansätze für die Entwicklung von unbemannten Fluggeräten JF - Ingenieurspiegel N2 - Wie sieht das unbemannte Flugzeug von Übermorgen aus? Dieser Frage stellen sich Forscher an der Fachhochschule Aachen. Die weltweit rasant fortschreitende Entwicklung des Marktes für unbemannte Fluggeräte (UAVs - „Unmanned Aerial Vehicles“) bietet großes Potenzial für Wachstum und Wertschöpfung. Unbemannte fliegende Systeme können – für bestimmte Anwendungsgebiete – wesentlich günstiger, kleiner und effizienter ausgelegt werden als bemannte Lösungen. Dabei sind sich viele Unternehmen über das mögliche Potential dieser Technologie noch gar nicht bewusst. Y1 - 2019 SN - 1868-5919 N1 - Project: UAV Design VL - 2019 IS - 1 SP - 67 EP - 68 ER - TY - JOUR A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Comparative assessment of parallel-hybrid-electric propulsion systems for four different aircraft JF - Journal of Aircraft N2 - Until electric energy storage systems are ready to allow fully electric aircraft, the combination of combustion engine and electric motor as a hybrid-electric propulsion system seems to be a promising intermediate solution. Consequently, the design space for future aircraft is expanded considerably, as serial hybrid-electric, parallel hybrid-electric, fully electric, and conventional propulsion systems must all be considered. While the best propulsion system depends on a multitude of requirements and considerations, trends can be observed for certain types of aircraft and certain types of missions. This Paper provides insight into some factors that drive a new design toward either conventional or hybrid propulsion systems. General aviation aircraft, regional transport aircraft vertical takeoff and landing air taxis, and unmanned aerial vehicles are chosen as case studies. Typical missions for each class are considered, and the aircraft are analyzed regarding their takeoff mass and primary energy consumption. For these case studies, a high-level approach is chosen, using an initial sizing methodology. Only parallel-hybrid-electric powertrains are taken into account. Aeropropulsive interaction effects are neglected. Results indicate that hybrid-electric propulsion systems should be considered if the propulsion system is sized by short-duration power constraints. However, if the propulsion system is sized by a continuous power requirement, hybrid-electric systems offer hardly any benefit. Y1 - 2020 U6 - https://doi.org/10.2514/1.C035897 SN - 1533-3868 VL - 57 IS - 5 PB - AIAA CY - Reston, Va. ER - TY - JOUR A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Impact of electric propulsion technology and mission requirements on the performance of VTOL UAVs JF - CEAS Aeronautical Journal N2 - One of the engineering challenges in aviation is the design of transitioning vertical take-off and landing (VTOL) aircraft. Thrust-borne flight implies a higher mass fraction of the propulsion system, as well as much increased energy consumption in the take-off and landing phases. This mass increase is typically higher for aircraft with a separate lift propulsion system than for aircraft that use the cruise propulsion system to support a dedicated lift system. However, for a cost–benefit trade study, it is necessary to quantify the impact the VTOL requirement and propulsion configuration has on aircraft mass and size. For this reason, sizing studies are conducted. This paper explores the impact of considering a supplemental electric propulsion system for achieving hovering flight. Key variables in this study, apart from the lift system configuration, are the rotor disk loading and hover flight time, as well as the electrical systems technology level for both batteries and motors. Payload and endurance are typically used as the measures of merit for unmanned aircraft that carry electro-optical sensors, and therefore the analysis focuses on these particular parameters. Y1 - 2018 U6 - https://doi.org/10.1007/s13272-018-0352-x SN - 1869-5582 print SN - 1869-5590 online VL - 10 IS - 3 SP - 843 PB - Springer ER - TY - JOUR A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Impact of Battery Performance on the Initial Sizing of Hybrid-Electric General Aviation Aircraft JF - Journal of Aerospace Engineering N2 - Studies suggest that hybrid-electric aircraft have the potential to generate fewer emissions and be inherently quieter when compared to conventional aircraft. By operating combustion engines together with an electric propulsion system, synergistic benefits can be obtained. However, the performance of hybrid-electric aircraft is still constrained by a battery’s energy density and discharge rate. In this paper, the influence of battery performance on the gross mass for a four-seat general aviation aircraft with a hybrid-electric propulsion system is analyzed. For this design study, a high-level approach is chosen, using an innovative initial sizing methodology to determine the minimum required aircraft mass for a specific set of requirements and constraints. Only the peak-load shaving operational strategy is analyzed. Both parallel- and serial-hybrid propulsion configurations are considered for two different missions. The specific energy of the battery pack is varied from 200 to 1,000 W⋅h/kg, while the discharge time, and thus the normalized discharge rating (C-rating), is varied between 30 min (2C discharge rate) and 2 min (30C discharge rate). With the peak-load shaving operating strategy, it is desirable for hybrid-electric aircraft to use a light, low capacity battery system to boost performance. For this case, the battery’s specific power rating proved to be of much higher importance than for full electric designs, which have high capacity batteries. Discharge ratings of 20C allow a significant take-off mass reduction aircraft. The design point moves to higher wing loadings and higher levels of hybridization if batteries with advanced technology are used. Y1 - 2020 U6 - https://doi.org/10.1061/(ASCE)AS.1943-5525.0001113 SN - 1943-5525 VL - 33 IS - 3 PB - ASCE CY - Reston, Va. ER - TY - JOUR A1 - Finger, Felix A1 - Bil, Cees A1 - Braun, Carsten T1 - Initial Sizing Methodology for Hybrid-Electric General Aviation Aircraft JF - Journal of Aircraft Y1 - 2019 U6 - https://doi.org/10.2514/1.C035428 SN - 1533-3868 VL - 57 IS - 2 SP - 245 EP - 255 ER - TY - JOUR A1 - Finger, Felix T1 - Senkrechtstarter: FH-Absolvent wird für Transportdrohne ausgezeichnet JF - campushunter: das etwas andere Karrieremagazin - Wintersemester 16/17 Y1 - 2016 SN - 2196-9426 IS - 17. Regionalausgabe Aachen SP - 116 EP - 117 PB - Campushunter Media CY - Heidelberg ER - TY - JOUR A1 - Finger, Felix T1 - Vergleichende Leistungs- und Nutzenbewertung von VTOL- und CTOL-UAVs JF - Luft- und Raumfahrt : informieren, vernetzen, fördern / Hrsg.: Deutsche Gesellschaft für Luft- und Raumfahrt Y1 - 2017 SN - 0173-6264 VL - 38 IS - 1 SP - 44 EP - 47 ER - TY - JOUR A1 - Fayyazi, Mojgan A1 - Sardar, Paramjotsingh A1 - Thomas, Sumit Infent A1 - Daghigh, Roonak A1 - Jamali, Ali A1 - Esch, Thomas A1 - Kemper, Hans A1 - Langari, Reza A1 - Khayyam, Hamid T1 - Artificial intelligence/machine learning in energy management systems, control, and optimization of hydrogen fuel cell vehicles N2 - Environmental emissions, global warming, and energy-related concerns have accelerated the advancements in conventional vehicles that primarily use internal combustion engines. Among the existing technologies, hydrogen fuel cell electric vehicles and fuel cell hybrid electric vehicles may have minimal contributions to greenhouse gas emissions and thus are the prime choices for environmental concerns. However, energy management in fuel cell electric vehicles and fuel cell hybrid electric vehicles is a major challenge. Appropriate control strategies should be used for effective energy management in these vehicles. On the other hand, there has been significant progress in artificial intelligence, machine learning, and designing data-driven intelligent controllers. These techniques have found much attention within the community, and state-of-the-art energy management technologies have been developed based on them. This manuscript reviews the application of machine learning and intelligent controllers for prediction, control, energy management, and vehicle to everything (V2X) in hydrogen fuel cell vehicles. The effectiveness of data-driven control and optimization systems are investigated to evolve, classify, and compare, and future trends and directions for sustainability are discussed. KW - optimization system KW - intelligent control KW - fuel cell vehicle KW - machine learning KW - artificial intelligence KW - intelligent energy management Y1 - 2023 U6 - https://doi.org/10.3390/su15065249 N1 - This article belongs to the Special Issue "Circular Economy and Artificial Intelligence" VL - 15 IS - 6 SP - 38 PB - MDPI CY - Basel ER - TY - JOUR A1 - Esch, Thomas A1 - Wolters, P. A1 - Salber, W. A1 - Geiger, J. T1 - Variable Ventilsteuerung und Direkteinspritzung - vom Wettbewerb zur Synergie JF - Motor und Umwelt 2001, Internal Combustion Engine Versus Fuel Cell - Potential and Limitations as Automotive Power Sources, Verbrennungsmotor versus Brennstoffzelle - Potenziale und Grenzen für den Automobilantrieb, Proc., Graz, AT, 6.-7. Sep, 2001 Y1 - 2001 N1 - Konferenz-Einzelbericht SP - 183 EP - 206 ER - TY - JOUR A1 - Esch, Thomas A1 - Saupe, T. A1 - Fahl, E. A1 - Koch, F. T1 - Verbrauchseinsparung durch bedarfsgerechten Antrieb der Nebenaggregate JF - Motortechnische Zeitschrift. 55 (1994), H. 7/8 Y1 - 1994 SN - 0024-8525 SP - 416 EP - 431 ER - TY - JOUR A1 - Esch, Thomas A1 - Salber, Wolfgang A1 - Wolters, Peter A1 - Geiger, José A1 - Dilthey, Jochen T1 - Synergies of variable valve actuation and direct injection JF - Direct injection SI engine technology 2002 : [SAE 2002 world congress, Detroit, Michigan, USA, March 4 - 7, 2002]. Y1 - 2002 SN - 0-7680-0961-8 N1 - Konferenz-Einzelbericht SP - 45 EP - 53 PB - Society of Automotive Engineers CY - Warrendale, Pa ER - TY - JOUR A1 - Esch, Thomas A1 - Salber, W. A1 - Kemper, Hans A1 - Staay, F. van der T1 - Der elektromechanische Ventiltrieb - Systembaustein für zukünftige Antriebskonzepte, Teil 2. JF - Motortechnische Zeitschrift (MTZ). Y1 - 2001 U6 - https://doi.org/10.1007/bf03227081 SN - 0024-8525 VL - 62 IS - 1 SP - 44 EP - 55 PB - Springer Nature CY - Basel ER - TY - JOUR A1 - Esch, Thomas A1 - Salber, W. A1 - Kemper, Hans A1 - Staay, F. van der T1 - Der elektromechanische Ventiltrieb - Systembaustein für zukünftige Antriebskonzepte, Teil 1. JF - Motortechnische Zeitschrift (MTZ). Y1 - 2000 U6 - https://doi.org/10.1007/bf03227081 SN - 0024-8525 VL - 61 IS - 12 SP - 826 EP - 836 PB - Springer Nature CY - Basel ER - TY - JOUR A1 - Esch, Thomas A1 - Pischinger, M. A1 - Hagen, J. A1 - Salber, W. T1 - Möglichkeiten der ottomotorischen Prozeßführung bei Verwendung des elektromechanischen Ventiltriebs Y1 - 1998 N1 - Konferenz-Einzelbericht : 7. Aachener Kolloquium Fahrzeug- u. Motorentechnik 05.-07. Okt. 1998, Bd. 2 SP - 987 EP - 1015 ER - TY - JOUR A1 - Esch, Thomas A1 - Pischinger, M. A1 - Göbel, T. T1 - Luft- und Kraftstoffzumessung bei Ottomotoren mit variabler Ventilsteuerung JF - Motortechnische Zeitschrift. 57 (1996), H. 2 Y1 - 1996 SN - 0024-8525 SP - 106 EP - 115 ER -