Numerical predictions of slot synthetic jets in quiescent surroundings

Abstract

A detailed numerical simulation is undertaken to investigate physical processes that are engendered in the injection of synthetic (zero-net-mass-flux) jets into quiescent surroundings. A complementary study of 3-D unsteady Reynolds-averaged Navier-Stokes (URANS) applied to a nominally 2-D problem is carried out and compared with experimental data that are obtained at corresponding conditions with the aim of achieving an improved understanding of fluid dynamics of synthetic jets flow fields in the quiescent surroundings. Making this investigation allows the computational framework to be verified, and so the basic properties of synthetic jets to be comprehended. Of particular interest is acquiring the turbulent structures from undigested experimental data. The hierarchy of established coherent structures presented here provides a credible explanation for the turbulent characteristics that are observed both in the experiments and the simulations. The computations are conducted by OpenFOAM C++ with two turbulence models, SST and RSM, are used to predict the synthetic jets flow fields. Although the models are capable of simulating time-averaged turbulent quantities, they underestimate phase-averaged turbulent quantities. As Reynolds number increases, the underestimates intensify.