Two-Dimensional Numerical Analysis of a Low-Re Turbulent Impinging Synthetic Jet

Synthetic jets are produced by the symmetric cyclic ejection and injection of fluid from a cavity. Due to the particular fluid dynamics, they generate an oscillating outward flow, which can be used as a cooling technique by impinging it onto a heated stationary surface. In small scale applications, synthetic jets have been found to remove heat more efficiently than steady jets at equal Reynolds numbers. Two-dimensional numerical simulations of this phenomenon have been presented in the literature, with turbulence as the preferred numerical model. The authors previously demonstrated that laminar flow has shown good to excellent agreement with experimental data under a certain range of jet-to-surface distance, frequency and Re. It was found that the most suitable turbulent model was the SST/k-omega. The heat transfer along the heated wall was influenced by the vortex dynamics. For cases with large jet-tosurface distance and low Reynolds number, the vortices were weak and with low vorticity. It was hypothesized that to the low heat transfer coefficient is due to the convection, conduction and radiation losses.