Lumped element modeling of piezoelectric-driven synthetic jet actuators

A lumped element model of a piezoelectric-driven synthetic-jet actuator is presented. A synthetic jet, also known as a zero net mass-flux device, uses a vibrating diaphragm to generate an oscillatory How through a small orifice or slot. In lumped element modeling, the individual components of a synthetic jet are modeled as elements of an equivalent electrical circuit using conjugate power variables. The frequency-response function of the circuit is derived to obtain an expression for Q(out)/V-ac, the volume flow rate through the orifice per applied voltage across the piezoceramic. The circuit is analyzed to provide physical insight into the dependence of the device behavior on geometry and material properties. Methods to estimate the model parameters are discussed, along with pertinent model assumptions, and experimental verification is presented of the lumped parameter models. In addition, two prototypical synthetic jet actuators are built and tested. Very good agreement is obtained between the predicted and measured frequency-response functions.