A Study on Synthetic Jet Actuator Diaphragm

Abstract

A synthetic jet actuator (SJA) is one of the most widely used active flow control device which uses a vibrating diaphragm enclosed within a cavity to generate the fluid jet. The effectiveness of the actuator greatly depends upon the design of cavity and orifice and the diaphragm properties. A lot of emphasis is being laid on the cavity and orifice design, but very few literatures can be found dealing with the diaphragm of the SJA. Thus, in this paper a study of the SJA diaphragm actuated by piezoelectric ceramics of different geometries is being presented. Three different diaphragm materials — brass, poly-silicon and aluminum and five different geometries of the piezoelectric actuators — annular disc shaped actuator patch, annular shaped actuator, rectangular shaped actuator patch and circular disc shaped actuator patch and two cantilever arrangements are being considered. A static analysis is carried out and a comparison of the parameters which affect the performance of the SJA is done. Frequency response analysis is also carried out to obtain a better understanding of the diaphragm's structural characteristics. The results thus obtained show that an annular disc piezoelectric patch configuration shows the best behavior as compared to the other actuator configurations and is closely followed by circular disc piezoelectric patch configuration.