Experimental and numerical investigation of the performance of vortex generators on separation control

An experimental wind tunnel study of the flow past a row of counter-rotating vortex generators mounted on top of a bump has been performed. All three velocity components axe measured in spanwise planes downstream of the vortex generators using Stereoscopic Particle Image Velocimetry, SPIV. The objective of this study is to investigate the effect of vortex generators in a separating, low Reynolds number, turbulent boundary layer over a geometry which is generating an adverse pressure gradient. The flow behaves as expected, in the sense that the vortices transport high momentum fluid into the boundary layer, making it thinner and more resistant to the adverse pressure gradient with respect to separation. The idea behind the experiments is that the results will be offered for validation of modeling of the effect of vortex generators using various numerical codes. Steady-state RANS computations have been carried out in parallel to the experiments. The computations axe able to capture the overall flow structure, but has difficulties predicting the flow in the separation region and the large scale convection due to the vortex generators.