Experimental Investigation of Propagation of Shockwave Induced Disturbances in Transonic Airfoils

摘要

The mechanism of buffeting was investigated in a wind tunnel on a transonic airfoil. A holographic high speed real time interferometer was developed to observe and analyze the entire flow field surrounding the airfoil. The information from interferograms was compared with results from hot film and pressure measurements. The results show that the shock oscillation can be described by an interaction of the shock with the boundary layer and the flow conditions at the trailing edge of the airfoil. The observed buffet frequencies are higher for an initially laminar boundary layer than for a turbulent boundary layer. Buffet frequency decreases with increasing Reynolds number in the case of a turbulent boundary layer.