Development of a Steady Vortex Generator Jet in a Turbulent Boundary Layer

Abstract

The development of a vortex generator jet within a turbulent boundary layer was studied by the particle image velocimetry method. Jet velocities ranging from one to three times greater than the freestream velocity were examined. The jet was pitched 45 deg and skewed 90 deg with respect to the surface and flow direction, respectively. The velocity field in planes normal to the freestream was measured at four stations downstream of the jet exit. The jet created a pair of streamwise vortices, one of which was stronger and dominated the flow field. The circulation, peak vorticity, and wall-normal position of the primary vortex increased linearly with the jet velocity. The circulation and peak vorticity decreased exponentially with the distance from the jet source for the jet-to-freestream velocity ratios of 2 and 3. The wandering of the streamwise vortex can be as much as ±30% of the local boundary layer thickness at the farthest measurement station.