Effect of Geometry on Control Authority of Plasma-Based Active Flow Control for Subsonic Jet Thrust Vectoring

Thrust vectoring, the controlled deflection of a jet to alter the angle of developed thrust, is currently implemented using complex, heavy, variable geometry nozzles to obtain hyper-maneuverability and vertical take-off/landing capabilities. Localized Arc-Filament Plasma Actuators (LAFPAs) azimuthally distributed at the jet exit have shown the ability to induce pressure asymmetries on a fixed-geometry “reaction surface” which curves away from the jet axis. It was also shown with PIV that these asymmetric pressure distributions correspond to jet deflections. This work investigates the effect of reaction surface geometry on the LAFPAs’ ability to induce pressure asymmetries over the reaction surface. Multiple reaction surfaces were 3D printed to independently vary the reaction surface length and backward facing step height. The effect of control at various excitation frequencies was documented using an array of static pressure taps embedded in each reaction surface. The 1 mm and 0.85 mm step heights were the most effective, inducing the highest magnitudes of pressure asymmetries at lower and higher Ste, while larger step heights resulted in audible resonance that likely competed with the LAFPAs’ ability to alter the development of the coherent structures. The longest tested reaction surface produces greater changes in pressure asymmetry with respect to the baseline and a much more abrupt change (as excitation frequency increases) between significant pressure asymmetry directed toward and away from the active LAFPAs.