Optimisation of a Rectangular Orifice Synthetic Jet Generator

A rectangular orifice synthetic jet may be an effective means of generating longitudinal embedded vortices within low Reynolds number boundary layers for flow control. There is relatively little data available relating to the jet characteristics as a function of key geometric parameters. A series of experimental measurements using a modular synthetic jet are reported in which orifice length and resonance cavity depth are varied for a single diaphragm system operating at optimum excitation frequency. The maximum time averaged jet velocity is seen to decrease with both increasing orifice length and increasing cavity depth. Orifice length/width ratios of less than 10 produce a more uniform jet velocity distribution.