Aerodynamics and Acoustics of Rotorcraft

Kurzfassung

A survey of the 75th Fluid Dynamics Panel Symposium is given. The paper concentrates on dynamic stall, experimental investigations on helicopter rotors, 3D aerodynamic prediction methods and acoustic prediction methods. CFD methods were applied to dynamic stall on oscillating airfoils. The agreement with experimental data is acceptable for light and medium stall if appropriate turbulence models are used and the transition is fixed. None of the methods was able to accurately predict deep dynamic stall. A large effort was spent for the investigation of the blade vortex interaction (BVI) noise. New national and multi-national experimental campaigns were conducted. Several researchers worked on the development and validation of aerodynamic and acoustic prediction methods for BVI. The efficiency of Higher Harmonic Control and of Individual Blade Control inputs for the reduction of BVI noise were investigated. The blade vortex miss distance was found to be the most important parameter for BVI noise. Methods for the prediction of high speed impulsive noise have been developed and encouraging results were presented.