Inst. Luft- und Raumfahrt

68 Items

Recent Submissions
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...

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...

Manual flying and energy awareness

Müller, Simon ; Schreiter, Karolin ; Luckner, Robert ; Manzey, Dietrich (2017)

In order to enable pilots to better maintain energy awareness and energy management in manual flight, a new concept has been proposed, which transfers the demand control principle of fly-by-wire control laws also to the control of thrust. It includes a total-energy-related augmented thrust controller combined with a modified cockpit instrumentation enriched by specific energy displays. In order...

Enhancing manual flight precision and reducing pilot workload using a new manual control augmentation system for energy angle

Schreiter, Karolin ; Müller, Simon ; Luckner, Robert ; Manzey, Dietrich (2017)

With rising demands on flight precision and more complex flight trajectories, pilots' workload during manual flight is increasing. This is especially the case for thrust and spoiler control during approach and landing. The presented nxControl system enables pilots to manually control the longitudinal load factor nx instead of engine parameters and spoiler deflections. This load factor is equiva...

Demand control law for total energy angle tested at manual steep approaches

Schreiter, Karolin ; Müller, Simon ; Luckner, Robert ; Manzey, Dietrich (2018)

With rising demands on flight precision and more complex flight trajectories, pilots' workload during manual flight is increasing. This is especially the case for flight path and speed control with thrust and spoilers during approach and landing. The objective of the nxControl system is to enable pilots to manually control the longitudinal load factor nx instead of engine parameters and spoiler...

Untersuchung der mentalen Repräsentation von Energiemanagement bei der Flugzeugführung zur Entwicklung eines Pilotenassistenzsystems

Müller, Simon ; Manzey, Dietrich ; Bleyer, Anne ; Schreiter, Karolin ; Voigt, Anja ; Luckner, Robert (2013)

Um die mentale Repräsentation des Energiemanagements bei der manuellen Flugzeugführung zu untersuchen, wurde eine Simulatorkampagne mit n = 12 lizenzierten Verkehrspiloten durchgeführt. Ihre Aufgabe war es, künstlich generierte Höhen- und Geschwindigkeitsablagen auf dem Gleitpfad des Instrumentenlandesystems (ILS) im Endanflug zu korrigieren. Dabei wurde untersucht, ob und inwiefern sie von dem...

nxControl instead of pitch-and-power

Schreiter, Karolin ; Müller, Simon ; Luckner, Robert ; Manzey, Dietrich (2014)

A command system for manual control of the longitudinal load factor (nx) of an aircraft is designed that completes existing flight control command systems (e.g. sidesticks normal load factor nz). nxControl's aim is to assist pilots during manual flight by reducing the workload for monitoring flight parameters and the controlling of thrust and airbrakes. Important for nxControl concept is the di...

Simulatorstudie zur Ermittlung mentaler Handlungsmodelle von Piloten beim Energiemanagement

Müller, Simon ; Schreiter, Karolin ; Manzey, Dietrich (2013)

Im Rahmen des Forschungsprojektes "nxControl" wurde eine Simulatorstudie mit zwölf lizenzierten Verkehrspiloten zur Ermittlung mentaler Handlungsmodelle beim Energieabbau durchgeführt. Die Aufgabe der Piloten war es, drei Sink- und drei Landeanflüge mit variierten Randbedingungen zu absolvieren. Anhand der Versuchsergebnisse sollen Empfehlungen für die pilotenzentrierte Entwicklung eines Assist...

nxControl instead of pitch-and-power: a concept for enhanced manual flight control

Müller, Simon ; Schreiter, Karolin ; Manzey, Dietrich ; Luckner, Robert (2016)

A command system for manual control of the longitudinal load factor in flight path direction of an aircraft is designed that completes existing flight control command systems (e.g. with sidesticks that command normal load factor). The system is called nxControl. It aims to assist pilots during manual flight by reducing the workload for monitoring flight parameters as well as for controlling thr...

Verbesserung von Flugpräzision und Arbeitsbeanspruchung bei manuellen RNP-Anflügen durch Vorgaberegler und Anzeigen für den Energiewinkel (nxControl)

Schreiter, Karolin ; Müller, Simon ; Luckner, Robert ; Manzey, Dietrich (2016)

Mit steigenden Präzisionsanforderungen bei immer komplexeren Flugtrajektorien erhöht sich die Arbeitsbeanspruchung der Piloten im manuellen Flug besonders bei der Ansteuerung von Triebwerken und Bremsklappen. Die konventionelle Steuerung über Hilfsparameter wie Triebwerksdrehzahl bzw. Hebelstellung erlaubt keine exakte Vorhersage der Zustandsänderung. Stattdessen muss abgewartet und die Eingabe...

nxControl: Konzept zur Vorgaberegelung für die Längsbeschleunigung des Flugzeugs

Schreiter, Karolin ; Müller, Simon ; Luckner, Robert (2013)

Der zukünftige Luftverkehr erfordert präzisere Einhaltung von komplexeren Trajektorien. Automatische Flugführung mittels Autopilot und Autothrottle erlauben bereits heute die Einhaltung komplexer Flugtrajektorien. Jedoch muss stets gewährleistet sein, dass die Piloten die erhöhten Anforderungen an die Bahnführung auch im manuellen Flug erfüllen können. Moderne Verkehrsflugzeuge sind mit elektro...

Auslegung und Validierung der Leistungsfähigkeit eines GBAS-CAT-II/III-L1-Bodensubsystems

Schüttpelz, André (2018)

Die vorliegende Arbeit behandelt die Auslegung und Validierung der Leistungsfähigkeitmeines Bodensubsystems zur Unterstützung satellitengestützter mit Präzisionsanflüge und Landungen mit bodengestützter Erweiterung (GBAS). Sie verfolgt das Ziel, die Reife der Technologie zur Durchführung von Präzisionsanflügen bis CAT-IIIb mit erweitertem Betriebskonzept zur reduzierten Staffelung während des...