11. Numerical Simulation of a Synthetic Jet Actuator for Active Flow Control

This chapter presents the results of numerical investigations of a synthetic jet actuator for an active flow control system. The Moving–Deforming-Mesh (MDM) method as a boundary condition is used to capture the real physical phenomenon and investigate the influence of the membrane amplitude, the forcing frequency, and cavity effect on the jet velocity. Different cases are investigated to maximize the jet velocity—an actuator with one and two membranes in a cavity, with perpendicular and parallel membranes. 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). Results of actuators operating at the two abovementioned forcing frequencies are presented. The simulation results show an increase in the jet velocity as a result of an increase in the membrane peak-to-peak displacement. Synthetic jet actuators’ impact on the flow separation reduction will be investigated on the bump model. Preliminary simulation results of the flow separation over the bump are presented in this chapter as well.