Performance Enhancement of a Vertical Stabilizer Using Synthetic Jet Actuators: Non-zero Sideslip

Abstract

Active flow control with synthetic jets has been shown to increase aerodynamic efficiency by delaying flow separation. Application of flow control to a vertical stabilizer of an aircraft could enable a significant size reduction of that stabilizer. Wind tunnel experiments were conducted at Rensselaer Polytechnic Institute on a swept back, tapered stabilizer with a 33% chord rudder. Flow control was implemented using eight synthetic jet actuators located just upstream of the hinge-line. The mechanism of enhancement was characterized with surface pressure measurements and stereoscopic particle image velocimetry (SPIV). Using flow control, the side force was increased by up to 20% at moderate rudder deflections with actuators operating at dimensionless frequency O(10). Actuating the synthetic jets with a pulse-modulated waveform yielded superior performance at high rudder deflections. The effect of spanwise spacing was also investigated, as was the relative effect of actuators at different spanwise locations. It was demonstrated that mid-span actuators provide the greatest contribution at moderate rudder deflections, and root (inboard) actuators provide the greatest contribution a high deflections. Given that separation propagates from tip to root as rudder deflection increases, this correlates well with SPIV measurements, which show that the effect of each actuator is predominantly on a region outboard of its own position.