Effective hydraulic resistance of a nozzle in an electrodynamic actuator generating hybrid-synthetic jet – Part I: Data acquisition

Hybrid-synthetic jet actuators combine the advantages of synthetic jets and steady jets in flow control applications. For the design–especially of no-moving-part fluidic actuator versions – it is important to know the properties of the jet generating nozzle. Its effective time-mean hydraulic resistance with superposed oscillatory flow is higher, sometimes substantially, than in the steady flow. In a recent publication [18], a law governing this increase was derived from experimental data obtained with piston-type actuator at small oscillation amplitudes (smaller than – or at most equal to - the steady flow component). In the present paper, the investigations are extended to the large-amplitude conditions, with nozzle flow reversal in a part of the cycle - and to the case of an electrodynamic actuator with compliant membrane.