Control of Unsteady Plasma Flows over Conical Forebody

Abstract

An experimental study of the active control of vortices over slender forebodies is performed on a 20° circular‐cone‐cylinder model using a pair of Single‐Dielectric‐Barrier‐Discharge (SDBD) plasma actuators combined with duty‐cycle technique. The tests are carried out in a low‐turbulence 3.0 m × 1.6 m low‐speed wind tunnel at an angle of attack of 45°. The Reynolds number based on the cone base diameter is 50 000. The results consist of measurements of circumferential pressure distributions over eight stations along the cone forebody, including one station using unsteady pressure tappings, under three different modes of controls: plasma‐off, plasma port‐on or starboard‐on, and plasma duty‐cycle actuation. The cross‐sectional side forces over the cone are calculated from the measured pressures. The ensemble and phase‐locked averaged loads at various duty cycles are investigated. The test results indicate that the variation of the phase‐locked‐averaged side force in a period of the duty cycle is a smooth‐wave curve rather than the square‐wave curve. The linearity of the controlled lateral forces and moments with respect to the duty cycle is improved over previous studies because of the improved design of the actuators.