Interaction of Pitched and Skewed Synthetic Jet with a Turbulent Boundary Layer

Detailed stereoscopic particle image velocimetry measurements of the flowfield associated with the interaction of a finite-span synthetic jet with a turbulent boundary layer over a flat plate were collected at a Reynolds number of [Formula: see text]. The changes in pitch and skew of the synthetic jet orifice revealed substantial differences in the nature of the formation and advection of the vortical structures generated at the jet orifice. Results are given for the induced vorticity, momentum change, and turbulent kinetic energy of these structures. When the synthetic jet orifice was normal to the surface and perpendicular to the freestream, with a skew angle of 45 deg, it produced a steady streamwise vortex in the far field similar to a vortex generated by a vortex generator. When the orifice was pitched at 45 deg without skew, the jet provided the greatest addition of streamwise momentum to the flow out of the four configurations tested and thereby has the greatest potential for mitigation of separation in flow control applications. Each case tested could have advantages and disadvantages in applications with distinct requirements.