Краткое описание

This work deals with numerical simulation of supersonic turbulent flows when shock/turbulent boundary layer interaction occurs. Such flows reveal the existence of complex mechanisms, which have to be well understood for an efficient design of propulsion systems. In this study, large eddy simulation is used to investigate unsteady mechanisms. Since a shock-capturing scheme is used, an hybrid numerical scheme has been developed to reduce its dissipative properties. The issue of the generation of coherent turbulent boundary conditions is also addressed. A method originally developed by Lund, based on a rescaling technique, has been modified by adjusting the scaling coefficient to provide smooth transition between the inner and the outer parts of the boundary layer. This modification is essential for avoiding the drift previously observed in the mean streamwise velocity profile. The obtained results are analysed and discussed in terms of mean and turbulent quantities. Excellent agreement between LES, DNS and experimental data is obtained. Especially, oscillations of the reflected shock occurring at low frequencies are observed, in agreement with experimental investigations. Moreover, simulations reveal the presence of such frequencies inside the recirculation bubble. This point gives credit to the hypothesis which presents the instabilities of the reflected shock as a consequence of the dynamic properties of the separated zone.