Use of Vortex Generators to Control Internal Supersonic Flow Separation

摘要

The flow separation in the supersonic flow of a Laval nozzle can be delayed when the turbulence of the flew close to the wall is increased. This was achieved in the present investigations by means of an array of obstacles composed fo V-shaped half-cylinders and by means of swirling jets issuing normally to the nozzle wall. The obstacles induce a shock wave and a following expansion wave, which form wavy lines in the spanwise direction. Because various changes of flow properties along streamlines crossing these waves, the secondary flow appears downstream fo the obstacles in the plane normal to the wall. This enhances mixing of air particles in the boundary layer and external flow. This effect seems to dominate the effect of the streamwise vortices observed downstream the V-shaped obstacle in the low-velocity subsonic flow.