Karl Nilssen​​​​

by Dr. Lance Traub, Karl Nilssen & Michael Sweet

Abstract​
 

An experimental investigation is presented that characterizes the performance of a piston based synthetic jet actuator. The actuator comprises a c cylinder with a thin slot spanning its length. As the piston reciprocates, fluid is discharged ahead of, and drawn in, behind it. Envisaged orientation is with the slot parallel to a wings leading edge, while the jet is ejected perpendicular to the surface. Characterization of the actuator includes temporal pressure and velocity measurement. An analytic prediction model was developed to aid in characterization. Results indicate that the maximum outflow velocities are achieved when the piston is near the end of its stroke, while internal pressures scale with the square of the piston velocity or actuation frequency. Examination of the actuators ability to control flow separation was established using a divergent ramp. As shown, the actuator is capable of achieving flow control, essentially due to the injection of streamwise vortices propagation from the slot ends.

Published in the Journal of Aircraft