Exploration of Under-Expanded Free and Impinging Supersonic Jet Flows

The impact of jets on a wall remains one of the most effective means allowing a significant increase in local exchanges of heat. These configurations are therefore particularly used in aerothermal systems. The literature reports several studies on the impact of moderately to strongly under-relaxed jets, both from an aeroacoustics and thermal point of view. Nevertheless, the aerothermal behavior and consequently the effects of exchange with the wall remain little known. Moreover, these flows appear to be difficult to simulate from a numerical point of view. We propose here to describe the first part of an experimental study focused on the description of the topology and dynamics of both free and impinged under-expanded jets with the aim to define an accurate database dedicated to the improvement of numerical flow models.