Implicit large eddy simulation of high-speed impinging jets

Abstract

The dynamic process to be characterized by the following narrative comprises a supersonic jet impinging onto a flat surface, which produces complex fluid dynamic phenomena that are dominated by the intrecate shockwave structure of the jet ([1] and [2]). Even though the mean solution is relatively well understood, the growing of unsteady instabilities in the shear layer at the nozzle gives rise to oscillations in the dominant flow structures which travelling upstream perturb again the shear layer completing a loop usually known as feedback model [3]. Regrettably, the exact dynamic of this phenomena and the influence of the different parameters involved on it is still not well understood. This configuration has been thoughtfully studied experimentally by [4]. An Implicit Large Eddy Simulation methodology has been used in the computations. Although LES simulations have demonstrated their ability to predict the behavior of weakly compressible turbulent flows [5], their applicability to supersonic configurations remains to be validated [6]. The present study seeks to understand the mechanisms leading to the appearance of instabilities in impinging jets. In the longer term, it is hoped that flow control guidelines will emerge from these types of studies.