Experimental investigation of convective heat transfer on a flat plate subjected to a transversely synthetic jet

Abstract

In this study, the effect of a synthetic jet on the heat transfer of flow over a flat plate is investigated experimentally. The experimental study is consist of a heater made of copper plate having constant heat flux located in the wind tunnel, and including a synthetic jet actuator injected into the stream by the entrance of plate. The synthetic jet is created by a piston–cylinder mechanism. In the investigations, the Reynolds number in the main stream, the frequency and amplitude of the actuator are changed while the geometry and Prandtl number remain constant for all cases and the effect of these parameters on the convective heat transfer is analyzed. The experiments are carried out at six different frequencies and four different amplitudes. To explain the heat transfer mechanism, the flow visualization is performed by using the smoke–wire method, and the instantaneous flow images are obtained. The experimental results reveal that there is a disruptive effect on the hydrodynamic boundary layer of the synthetic jet actuator. The obtained results are given as dimensionless parameters. It is observed that, the cycle-averaged Nusselt number increases with the increase of both Womersley number (Wo) and dimensionless amplitude (Ao).