Alleviation of self-support in dual synthetic jet and its self-similarity of streamwise momentum flux

Abstract

A dual synthetic jet (DSJ) actuator has two chambers sharing the same wall equipped with a single oscillatory diaphragm. The novel structure doubles the function of synthetic jet (SJ) actuator and brings it merits that a traditional synthetic jet actuator does not have like resolving the problems of pressure loading and energy inefficiency. However, self-support, which is unique to DSJ, may result in weak jets or even no jets. In order to effectively solve the self-support problem of DSJ and further improve its performance, this paper proposes a novel DSJ exit structure with a penetrating channel. The experimental and numerical investigations prove that the jet penetration depth and streamwise momentum flux of DSJ are increased by nearly 25%–50%. Furthermore, through the analysis of a large number of simulation data, it is found that the streamwise momentum flux distributions of DSJ under random driving frequency and driving amplitude can be expressed by a unified mathematical fitting formula, that is, the streamwise momentum flux has self-similarity. This criterion can efficiently and quickly calculate the SJ/DSJ driving parameters required for effectively controlling the flow field.