ZURUECK HOCH VOR INHALT SUCHEN

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Proposing Institution

Deutsches Zentrum für Luft- und Raumfahrt e.V. Göttingen
Project Manager

Dr. Anthony Gardner
Bunsenstr. 10
37073 Göttingen
Abstract
The project “Investigation of blade tip vortices” consists of three sub projects. Besides the first sub project, which is a grid sensitivity study, the other sub projects focus on blade tip vortices of a rotating and pitching blade. Blade tip vortices are still a challenging flow phenomena regarding helicopter aerodynamics. Like fixed wing aircraft, helicopters produce blade tip vortices. These vortices will be pushed downwards during hover, but in other flight conditions like forward flight or slow descending flight the vortices can be reingested by the rotor, striking the other blades leading to blade-vortex interaction. The blade-vortex interaction can lead to a limitation of the flight envelope of the helicopter when it causes the flow on the highly loaded rotor to stall, causing dynamic stall. These encounters lead to high structural loads and increased vibration which is avoided by limiting the flight envelope.Simulations of a simple laboratory rotor experiment for which good calibration data is available will be done. The rotor test facility (RTG) in Göttingen is a new facility in which a rotor with axial inflow is operated with high cyclic pitch. This generates a highly unsteady and three dimensional flow which is periodic in azimuthal position. The flow situation is analogous to that for helicopters in forward flight, but without the Mach and Reynolds number variation typical of that flow situation. A number of computations will be performed to compute the RTG experiments, concentrating on the correct modelling of the vortex generation and time/spatial history after generation, with comparison to the validation experiments available. The project concentrates on the vortex parameters including vortex strength, swirl velocity distribution and radius after generation of the vortex and the geometry of the combination of initial features leading to the generation of the vortex.

Impressum, Conny Wendler