Experimental Investigation of Shock-Vortex Interaction

Abstract Supersonic vortex breakdown, caused by the interaction of slender streamwise vortices with normal or oblique shocks, is a flow phenomenon that cannot be explained in full detail, yet. The experiments of this study are designed to give somewhat more insight into the development of the velocity profiles of vortices with a high circulation as they travel downstream, the structure of the flow field in the shock–vortex interaction region, and the dependence of the global flow field on the parameters, which can cause vortex breakdown. The objective of this study is to investigate the physical mechanisms, which lead to vortex breakdown during shock–vortex interaction using optical flow visualization and velocity measurement techniques. First, velocity measurements of slender streamwise vortices are performed in the supersonic wind tunnel facility of the Institute of Aerodynamics. The circumferential and axial velocity profiles of an undisturbed supersonic wing-tip vortex and a vortex generated with swirl vanes are measured using a two-component Laser Doppler Velocimetry system. Next, the interaction between these vortices and normal as well as oblique shocks is investigated at several supersonic Mach numbers. A parameter study is carried out to determine the influence of freestream Mach number, shock strength, and swirl ratio of the vortex on vortex breakdown. In order to obtain information about the global structure of the flow field, the flow is visualized using the schlieren and the color-schlieren technique. For a more detailed analysis of shock–vortex interaction the differential interferometry is applied. For oblique shock–vortex interaction, the velocity distribution in the interaction region of the vortex and the shock is investigated by Particle-Image Velocimetry for selected parameter combinations based upon the results of the parameter study…