INFLUENCE OF MEMBRANE AMPLITUDE AND FORCING FREQUENCY ON SYNTHETIC JET VELOCITY

Abstract

This paper presents the results of numerical investigations of a synthetic jet actuator for an active flow control system. The Moving Deforming-Mesh method as a boundary condition is used to capture the real physical phenomenon. This approach allows precise investigation of the influence of the membrane amplitude, the forcing frequency and cavity effect on the jet velocity. A synthetic jet actuator is simulated using a membrane perpendicular to the surface arrangement. Two cases are investigated to maximize the jet velocity – an actuator with one and two membranes in a cavity. Two main forcing frequencies can be specified in the synthetic jet actuator application. One corresponds to the diaphragm natural frequency and the other corresponds to the cavity resonant frequency (the Helmholtz frequency). This study presents the results of actuators operating at the two abovementioned forcing frequencies. The simulation results show an increase in the jet velocity as a result of an increase in the membrane peak-topeak displacement. This study was a preliminary study of the synthetic jet actuator for single and double membrane systems. The optimization process of the synthetic jet actuator geometry and parameters is ongoing. Numerical results obtained in these investigations are to be validated in the experimental campaign.

Keywords

• synthetic jet
• active flow control
• flow separation