Inst. Luft- und Raumfahrt

78 Items

Recent Submissions
Numerical Assessment of Virtual Control Surfaces for Load Alleviation on Compressor Blades

Motta, Valentina ; Malzacher, Leonie ; Peitsch, Dieter (2018-01-17)

Virtual control surfaces for the optimization of steady and unsteady airloads on a compressor cascade are assessed numerically. The effects of mechanical surfaces are realized with plasma actuators, located both on the pressure and on the suction side of the blade trailing edge. Suction side plasma actuation is thought to reproduce the effects of mechanical wing spoilers, whereas pressure side ...

Präzisere Echtzeit-Flugsimulation kleiner Nutzflugzeuge durch Integration feingranularer Teilmodelle

Meyer-Brügel, Wolfram (2019)

Die Technologien und Anwendungsgebiete für UAV und kleine Nutzflugzeuge haben im zivilen Bereich in letzter Zeit eine rasante Entwicklung erfahren. Da der Betrieb dieser Systeme mit erheblichen Sicherheitsrisiken für den Luftverkehr verbunden ist, wird für die Soft- und Hardwareentwicklung der erforderlichen komplexen und sicherheitskritischen Avioniksysteme ein Prozess benötigt, der eine vergl...

An extended modal approach for nonlinear aeroelastic simulations of highly flexible aircraft structures

Ritter, Markus Raimund (2019)

Some classes of aircraft are characterized by highly flexible wings undergoing large structural deformations in steady and maneuvering flight. In most cases this flexibility is the result of a high aspect ratio, which is in turn forced by dedicated design criteria such as the reduction of the induced drag. Prominent examples for such configurations are High Altitude Long Endurance (HALE) aircra...

Investigations on the current and future use of radio frequency allocations for small satellite operations

Buscher, Martin (2019)

Global radio frequency spectrum use for satellite communication is a present-day challenge that has been aggravated by the increased launch of small satellites during the past 15 years. This thesis aims to examine both regulatory and technical aspects of spectrum use. The focus of this examination is on frequency bands that are commonly used by small satellites and on those bands that might be ...

Flight mechanics and flight control for a multibody aircraft

Köthe, Alexander (2019)

Aircraft operating as so-called High Altitude Platform Systems (HAPS) have been considered as a complementary technology to satellites since several years. These aircraft can be used for similar communication and monitoring tasks while operating at a fraction of the cost. Such concepts have been successfully tested. Those include the AeroVironment Helios and the Airbus Zephyr, with an endurance...

Data for A Tutorial on the Proper Orthogonal Decomposition

Weiss, Julien (2019-06-19)

Experimental database from AIAA Paper 2019-3333 (A Tutorial on the Proper Orthogonal Decomposition) presented at the AIAA Aviation Conference 2019 in Dallas, Texas, on June 19th, 2019. The database consits of 2D velocity fields measured by PIV that are used to generate the figures in the paper.

A Tutorial on the Proper Orthogonal Decomposition

Weiss, Julien (2019)

This tutorial introduces the Proper Orthogonal Decomposition (POD) to engineering students and researchers interested in its use in fluid dynamics and aerodynamics. The objectives are firstly to give an intuitive feel for the method and secondly to provide example MATLAB codes of common POD algorithms. The discussion is limited to the finite-dimensional case and only requires knowledge of basic...

Untersuchung von PIO-Tendenzen bei plötzlichen Umschaltungen in der Flugdynamik

Schönfeld, Andrej (2019)

Bisher wurden Kopplungsphänomene des Gesamtsystems Pilot-Flugzeug (Piloteninduzierte Schwingungen, PIO) nach einer Umschaltung im Flugregelungssystem nur unzureichend systematisch untersucht. In den letzten Jahren traten jedoch einige Vorfälle in der zivilen Luftfahrt auf, die zeigten, dass schwere Vorfälle entstehen können, wenn Umschaltungen der Flugregelungsgesetze involviert sind. Die vorli...

Methodik zur Bewertung von Flugverfahren hinsichtlich Fluglärm und weiteren Kriterien

Müller, Marvin ; Strümpfel, Christoph (2019-01)

Geänderte Betriebsverfahren an Flughäfen können für Bewohner von flughafennahen Gebieten verminderten Fluglärm und verbesserte Luftqualität bedeuten, während in anderen Gebieten im Umkreis von Flughäfen gegensätzliche Effekte zu beobachten sind. Folglich ist an Flughäfen, insbesondere jenen in Industrieländern, ein massiver Interessenkonflikt während des Flugbetriebs und in Hinblick auf Änderun...

Control of secondary flow structures on a highly loaded compressor cascade

Zander, Vincent ; Nitsche, W. (2013)

This paper presents detailed flow-field measurements for a compressor cascade equipped with synthetic jet actuators for active flow control. The synthetic jets are mounted on the cascade sidewall and the suction side surface of the blade to reduce the total pressure loss caused by strong secondary flow structures developing in the passage. There are certain articles reporting that synthetic jet...

Active flow control by means of synthetic jets on a highly loaded compressor cascade

Zander, Vincent ; Hecklau, Martin ; Nitsche, W. ; Huppertz, A. ; Swoboda, M. (2011)

This article presents the potential of active flow control to increase the aerodynamic performance of highly loaded turbomachinery compressor blades. Experimental investigations on a large-scale compressor cascade equipped with 30 synthetic jet actuators mounted to the sidewalls and the blades themselves have been carried out. Results for a variation of the inflow angle, the jet amplitude, and ...

Studies on conventional cutting of intermetallic nickel and titanium aluminides

Uhlmann, Eckart ; Herter, S. (2006)

Owing to the high percentage of covalent bonds, intermetallic nickel and titanium aluminides have specific physical and chemical characteristics that predestine them for components under high thermal and mechanical load. However, the relatively low ductility and thermal conductivity at room temperature, linked to high tensile strength, impede the machining with geometrically defined cutting edg...

Monitoring of slowly progressing deterioration of computer numerical control machine axes

Uhlmann, Eckart ; Geisert, C. ; Hohwieler, E. (2008)

The feed axes of computer numerical control (CNC) grinding machine tools are among the most mechanically stressed components of machine tools owing to the high process forces and rough manufacturing environment which they encounter. The resulting wear and tear depends strongly on the product range and the manner of machine operation. To counteract a functional deficiency of these central machin...

A wall shear stress measurement technique using the thermal wakes of small heated spots

Rudolph, I. ; Reyer, M. ; Nitsche, W. (2009)

A new thermo-optical method for the measurement of wall shear stresses is presented. The technique exploits that the surface temperature field and the near wall flow are closely linked by correlating the thermal wakes of small heated spots with the wall shear stress. Numerical as well as experimental results are presented and different correlation and design parameters are examined. In contrast...

Stability Improvement of Motion of a Rotor With an Active Control Method

Liao, M. F. ; Gasch, Robert ; Kolk, O. ; Kletschkowski, Thomas (2000)

The so-called phase-locked delayed feedback control method is applied to a Jeffcott rotor supported by rolling-element bearings but with negative damping and then to the same rotor supported hy journal bear ings, to improve the stability of motion of the rotor. The control parameters arc determined in terms of the characteristic equation of the controlled rotor. The results of numerical simulat...

[Book Review:] Contact mechanics and friction: physical principles and applications

Knothe, Klaus (2011)

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A Flight Simulator Study to Evaluate Manual Flying Skills of Airline Pilots

Haslbeck, Andreas ; Kirchner, Paul ; Schubert, Ekkehart ; Bengler, Klaus (2014)

This paper reports an experimental study with the objective to assess pilots’ raw-data-based flight performance which is affected by long-term practice and structured training. Fifty-seven airline pilots with different levels of aviation experience scheduled on an Airbus fleet, representing contrary levels of practice and training, had to fly a simulated 45 minutes approach and landing scenario...

Aeroelastic assessment of a highly loaded high pressure compressor exposed to pressure gain combustion disturbances

Bicalho Civinelli de Almeida, Victor ; Peitsch, Dieter (2018-10-15)

A numerical aeroelastic assessment of a highly loaded high pressure compressor exposed to flow disturbances is presented in this paper. The disturbances originate from novel, inherently unsteady, pressure gain combustion processes, such as pulse detonation, shockless explosion, wave rotor or piston topping composite cycles. All these arrangements promise to reduce substantially the specific fue...

Contributions to the advance of the integration density of CubeSats

Grau, Sebastian (2019)

This thesis investigates potential technologies to increase the integration density of CubeSats. Observations of the CubeSat market and missions are recorded in order to derive design criteria for high performance single unit CubeSats. A promising approach to increased integration density is relocation of the components of multiple satellite subsystems to form a highly integrated, multi-functio...

Aeroakustische Auslegung von Triebwerksfans mittels multidisziplinärer Optimierungen

Jaron, Robert (2018)

Fan noise is the dominant noise source in modern aircraft engines with high bypass ratios. Therefore the consideration of the noise reduction during the design of a fan stages becomes more and more important. In state-of-the-art design processes of fan stages the aerodynamic performance and the mechanical stability is automatically optimized by means of numerical simulations of the parametrized...