Management of a Stronger Wall Jet by a Streamwise Vortex with Periodic Perturbation. Mean Flow Properties and Evolution of a Streamwise Vortex.

Abstract

Effect of periodic perturbation was investigated experimentally on the management of a stronger wall jet with a streamwise vortex. A half-delta wing located on the wall generates the streamwise vorticity and the periodic perturbation is added by varying in angle of attack of the wing. Measurements of mean velocity, secondary velocity vectors, and streamwise vorticity were examined to see effect of the periodic perturbation on the evolution process of the wall jet and streamwise vortex. The periodic perturbation accelerates development of vortex radius in spanwise direction over the initial stage and increases relative strength of spanwise secondary velocity vector to the transverse velocity vector. The streamwise momentum flux is increased by interaction between streamwise vortex and wall jet. However, the periodic perturbation reduces increasing rate of the momentum flux.