Active control of jet-plate interaction noise for excited jets by plasma actuators

Abstract

This paper examines the possibility of controlling jet-wing interaction noise by plasma actuators. The low-frequency part of the jet installation noise is considered as produced by the diffraction of instability wave packets developing in the jet shear layer. Thus, the main idea of noise control comes to the attempt to reduce the amplitude of these wave packets near the wing trailing edge. A simplified jet-plate configuration is studied experimentally for jet Mach numbers ranging from 0.4 to 0.6. To avoid additional complications related to the control of stochastic signals in the first step, the jet is excited by a loudspeaker at a frequency corresponding to Strouhal number 0.6. Acoustic forcing generates axisymmetric instability wave in the jet shear layer, which is the object of control. The control action is implemented by a high-frequency dielectric barrier discharge (HF DBD) plasma actuator with a ring-like electrode mounted inside the nozzle near the exit. It is demonstrated that installation noise can be significantly suppressed if the plasma actuator generates instability wave with the amplitude equal to that of the excited by the loudspeaker, but in antiphase to it, and vice versa, if these instability waves are in phase, installation noise increases by about 6 dB. The obtained results support the idea that low-frequency jet-wing installation noise can be controlled in a linear framework.