Effects of Jet-Orifice Shape on the Flow-Control Effectiveness of Air-Jet Vortex Generators

An experimental investigation was carried out to assess the effectiveness of non-circular air-jet vortex generators (AJVGs) in controlling shock-induced separations. Single rows of spanwise-inclined AJVGs with circular, rectangular, and four triangular orifice shapes were tested in an incoming supersonic crossflow at Mach 2.52 and \(Re_\theta = 8225\) . All cases were characterised by the same hydraulic diameter for comparability. Surface oil-flow visualisations and PIV in a wall-parallel plane are used for flow diagnostics. The results reveal an improved performance by all non-circular AJVGs in controlling the shock-induced separation, in comparison to the traditional circular AJVG. The improved effectiveness is expected to be a result of increased turbulent mixing and favourable jet/jet interactions between neighbouring jets in the array.