École Nationale Supérieure de
Techniques Avancées

Abstract

This research internship focused on the numerical simulation of a compressible unsteady flow in an S-shaped duct (S-duct), using the Lattice Boltzmann Method (LBM) and the Large Eddy Simulation model for turbulence. The S-duct is used in the aerospace, aeronautics and automotive industries. It is representative of many complex aerodynamic phenomena. The aim of the internship was to validate the code using experimental data, and to find an optimal parameter configuration for it. The results were insensitive to certain parameters such as the pressure gradient coefficient and the mass conservation model. Other parameters had a greater impact : a finer mesh gives a more stable flow, but dissipates more energy and thus ’hides’ the detachment zone ; an additional artificial injection of turbulence improves the mixing of the flow, but drags it closer to the walls and reattaches it more quickly after detachment ; and a very high STR makes the detachment and recirculation zone disappear completely, and deviates significantly from the experimental results.