TY - JOUR A1 - Mertens, Josef T1 - Multi point design challenges for supersonic transports JF - 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 Y1 - 1998 SN - 92-837-1007-X SP - 8.1 EP - 8.12 PB - Research and Technology Organization CY - Neuilly-sur-Seine ER - TY - JOUR A1 - Mertens, Josef T1 - Laminar flow for supersonic transports JF - Proceedings : March 16 - 18, 1992, Congress Centrum, Hamburg, Federal Republic of Germany / organized jointly by: Deutsche Gesellschaft für Luft- und Raumfahrt e.V. ... [Programme committee J. Szodruch ...] Y1 - 1992 SN - 3-922010-73-3 N1 - DGLR-Bericht ; 92,06 SP - 319 EP - 323 PB - DGLR CY - Bonn ER - TY - JOUR A1 - Mertens, Josef T1 - Aerodynamische Ziele des Adaptiven Flügels (ADIF). JF - DGLR-Jahrbuch 1998 Bd. 1 Y1 - 1998 N1 - DGLR-JT98-213 SP - 47 EP - 52 ER - TY - JOUR A1 - Mertens, Josef T1 - Einige herausragende Ergebnisse des Technologieprogramms "Reduktion des Aerodynamischen Widerstands (RaWid)" JF - DGLR-Jahrbuch 1999 Bd. 3 Y1 - 1999 N1 - DGLR-JT99-047 SP - 1461 EP - 1468 ER - TY - BOOK A1 - Mertens, Josef T1 - Reduktion des aerodynamischen Widerstands (RaWid) : Abschlußbericht ; Laufzeit des Vorhaben, Berichtszeitraum: 01.07.1995 bis 31.12.1998 / Verf.: J. Mertens Y1 - 1999 N1 - Förderkenzeichen BMBF 20 A 9595 A. Engl. Zsfassung u.d.T.: Reduction of aerodynamis drag (RaWid) - final report . auch als elektronisches Dokument vorh. PB - DaimlerChrysler Aerospare Airbus GmbH CY - Hamburg ER - TY - BOOK A1 - Mertens, Josef T1 - Reduktion des aerodynamischen Widerstands (RaWid) : Abschlußbericht ; Laufzeit des Vorhaben, Berichtszeitraum: 01.07.1995 bis 31.12.1998 / Verf.: J. Mertens Y1 - 1999 N1 - Parallel als gedruckte Ausgabe erschienen PB - DaimlerChrysler Aerospare Airbus GmbH CY - Hamburg ER - TY - CHAP A1 - Mertens, Josef ED - Nitsche, Wolfgang T1 - Some important results of the technology programme RaWid T2 - 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) Y1 - 1999 SN - 978-3-663-10903-7 (Print) SN - 978-3-663-10901-3 (Elektronisch) U6 - http://dx.doi.org/10.1007/978-3-663-10901-3_41 SP - 315 EP - 322 PB - Springer Fachmedien CY - Wiesbaden ER - TY - CHAP A1 - Mertens, Josef A1 - Becker, K. ED - Ballmann, Josef T1 - Numerical solution of flow equations : an aircraft designer's view T2 - 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) N2 - 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. Y1 - 1989 SN - 3-528-08098-1 U6 - http://dx.doi.org/10.1007/978-3-322-87869-4_41 N1 - International Conference on Nonlinear Hyperbolic Problems <3, 1988, Aachen> SP - 403 EP - 412 PB - Vieweg CY - Braunschweig ER - TY - JOUR A1 - Mertens, Josef A1 - Henke, Rolf T1 - Adaptive technologies for future civil air transport JF - Air & Space Europe. 3 (2001), H. 3-4 Y1 - 2001 SN - 1247-5793 SP - 80 EP - 82 ER - TY - JOUR A1 - Mertens, Josef A1 - Hünecke, Klaus T1 - Experimentelle Untersuchung zur Landeeigenschaft von Hyperschall-Fluggeräten / Hünecke, Klaus ; Mertens, Josef JF - DGLR-Jahrbuch 1988 Bd. 1 Y1 - 1988 N1 - DGLR-88-123 SP - 706 ER - TY - JOUR A1 - Mertens, Josef A1 - Kelm, R. A1 - Velden, A. van der T1 - Interdisziplinäre Auslegung eines Verkehrsflugzeugflügels JF - DGLR-Jahrbuch 1999 Bd. 3 Y1 - 1999 N1 - DGLR-JT99-156 SP - 1605 EP - 1610 ER - TY - JOUR A1 - Mertens, Josef A1 - Klevenhusen, K. D. A1 - Jakob, H. T1 - Accurate Transonic Wave Drag Prediction Using Simple Physical Models JF - AIAA-Journal. 25 (1987), H. 6 Y1 - 1987 SN - 0001-1452 SP - 799 EP - 805 ER - TY - PAT A1 - Mertens, Josef A1 - Lajain, Henri T1 - Method of fabricating leading edge nose structures of aerodynamic surfaces : patent no.: US 6,415,510 B2 ; date of patent: Jul. 9, 2002 Y1 - 2002 N1 - Volltext auch in der Datenbank http://publikationen.dpma.de/ zu finden unter der Nummer US000006415510B2 PB - United States Patent and Trademark Office CY - [Washington, DC] ER - TY - JOUR A1 - Mertens, Josef A1 - Röger, Wolf T1 - F-Schlepp: Problem Taumelschwingung JF - Aerokurier. 44 (2000), H. 10 Y1 - 2000 SN - 0341-1281 N1 - in der Bereichsbibliothek unter der Signatur 23 Z 391-2000 SP - 73 EP - 73 ER - TY - PAT A1 - Mertens, Josef A1 - Velden, Alexander van der A1 - Kelm, Roland T1 - Flugzeug mit Flügeln, deren maximaler Auftrieb durch steuerbare Flügelkomponenten veränderbar ist : Offenlegungsschrift DE102004045732 ; Offenlegungstag: 30.03.2006 = Aircraft with wings whose maximum lift can be altered by controllable wing components Y1 - 2006 N1 - Zugleich EP1791755A1. - Volltext über Datenbank: http://publikationen.dpma.de/ PB - Deutsches Patent- und Markenamt CY - München ER - TY - BOOK A1 - Mertens, Josef A1 - Velden, Alexander van der A1 - Kelm, Roland A1 - Kokan, David T1 - Application of MDO to large subsonic transport aircraft Y1 - 2000 N1 - Aerospace Sciences Meeting and Exhibit <38, 2000, Reno, NV> ; (AIAA Paper ; 00-0844) PB - American Institute of Aeronautics and Astronautics CY - Reston, Va. ER - TY - JOUR A1 - Meyer, Max-Arno A1 - Granrath, Christian A1 - Feyerl, Günter A1 - Richenhagen, Johannes A1 - Kaths, Jakob A1 - Andert, Jakob T1 - Closed-loop platoon simulation with cooperative intelligent transportation systems based on vehicle-to-X communication JF - Simulation Modelling Practice and Theory Y1 - 2021 U6 - http://dx.doi.org/10.1016/j.simpat.2020.102173 SN - 1569-190X VL - 106 IS - Art. 102173 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Möhren, Felix A1 - Bergmann, Ole A1 - Janser, Frank A1 - Braun, Carsten T1 - On the determination of harmonic propeller loads T2 - AIAA SCITECH 2023 Forum N2 - 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. Y1 - 2023 U6 - http://dx.doi.org/10.2514/6.2023-2404 N1 - AIAA SCITECH 2023 Forum, 23-27 January 2023, National Harbor, MD & Online PB - AIAA ER - TY - JOUR A1 - Möhren, Felix A1 - Bergmann, Ole A1 - Janser, Frank A1 - Braun, Carsten T1 - On the influence of elasticity on propeller performance: a parametric study JF - CEAS Aeronautical Journal N2 - The aerodynamic performance of propellers strongly depends on their geometry and, consequently, on aeroelastic deformations. Knowledge of the extent of the impact is crucial for overall aircraft performance. An integrated simulation environment for steady aeroelastic propeller simulations is presented. The simulation environment is applied to determine the impact of elastic deformations on the aerodynamic propeller performance. The aerodynamic module includes a blade element momentum approach to calculate aerodynamic loads. The structural module is based on finite beam elements, according to Timoshenko theory, including moderate deflections. Several fixed-pitch propellers with thin-walled cross sections made of both isotropic and non-isotropic materials are investigated. The essential parameters are varied: diameter, disc loading, sweep, material, rotational, and flight velocity. The relative change of thrust between rigid and elastic blades quantifies the impact of propeller elasticity. Swept propellers of large diameters or low disc loadings can decrease the thrust significantly. High flight velocities and low material stiffness amplify this tendency. Performance calculations without consideration of propeller elasticity can lead to decreased efficiency. To avoid cost- and time-intense redesigns, propeller elasticity should be considered for swept planforms and low disc loadings. KW - Propeller KW - Finite element method KW - Blade element method KW - Propeller elasticity KW - Aeroelasticity Y1 - 2023 U6 - http://dx.doi.org/10.1007/s13272-023-00649-y SN - 1869-5590 (Online) SN - 1869-5582 (Print) N1 - Corresponding author: Felix Möhren VL - 14 SP - 311 EP - 323 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Neu, Eugen A1 - Janser, Frank A1 - Khatibi, Akbar A. A1 - Braun, Carsten A1 - Orifici, Adrian C. T1 - Operational Modal Analysis of a wing excited by transonic flow JF - Aerospace Science and Technology N2 - 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. Y1 - 2016 U6 - http://dx.doi.org/10.1016/j.ast.2015.11.032 SN - 1270-9638 VL - 49 SP - 73 EP - 79 PB - Elsevier CY - Amsterdam ER -