Large eddy simulation of turbulent flows in reversing systems

Abstract

Curved flows observed in aeronautical reversing systemsare studied using large eddy simulation (LES).To estimate the prediction capabilities of LES, acurved mixing layer is first simulated. The major effect of curvature is to decrease the level of turbulent fluctuations, a decrease that is followed by an overshoot of fluctuations whenthe flow relaxes further downstream. These observations agree well with previous experimental investigations of curved mixing layers. The simulations of a thrust-reverser test case reveal that large scale spanwise motions play a crucial role.Specifically, they overcome the decrease of turbulent fluctuations in the curved zone. The properties of the flow contributing to the reverse thrust developing at the exit of the reversermay then strongly depend on the behaviour of the unsteadycoherent large scales.

This article was chosen from Selected Proceedings of the 1st French Seminar on Turbulence and Space Launchers (CNES-Paris, 13-14 June 2002) ed P Vuillermoz, P Comte and M Lesieur.