Modelling of the characteristics of synthetic jet actuators

In this paper, a simple static compressible model and a dynamic incompressible model for circular synthetic jet actuators are described. They are used to investigate the effect of changing actuator geometrical and operating parameters on the magnitude of jet peak velocity at the orifice exit. Depending on the flow conditions inside the orifice duct, the actuator may operate in two distinct regimes, i.e. the Helmholtz resonance regime and the non-Helmholtz resonance regime. In the Helmholtz resonance regime, the resultant synthetic jet is generated by the mass physically displaced by the oscillating diaphragm coupled with the Helmholtz resonance in the actuator. In the non-Helmholtz resonance regime, the Helmholtz resonance is completely damped by viscous effect such that the jet is produced by the diaphragm oscillation alone. An attempt is made to establish the relation among actuator geometrical and operating parameters at the optimum condition which yields the maximum jet peak velocity at a given diaphragm displacement. A procedure that leads to an optimal actuator design for flow control on aircraft is also proposed. and Zhong, S. Published by the American Institute of Aeronautics and Astronautics, Inc.