PSP and PIV Investigations on the VFE-2 Configuration in Sub- and Transonic Flow

Abstract

An overview is given about investigations on a 65° delta wing using the Pressure Sensitive Paint (PSP) and Particle Image Velocimetry (PIV) techniques in the framework of the International Vortex Flow Experiment 2 (VFE-2). For the delta wing equipped with rounded leading edges the occurrence of a flat vortical structure close to the surface of the suction side, the onset of the primary vortex and the development of a vortex system consisting of an inner and outer vortex is described for a Mach number of 0.4 in dependency of the angle of attack and the Reynolds number. The Q-criterion is used to analyze the velocity data and calculate the circulation of the vortices. Results obtained under transonic conditions (M = 0.8) showing a sudden occurrence of vortex breakdown above the delta wing, which most probably is induced by shock waves, are described too.