Wall-Modelled Large-Eddy Simulation of a hot Jet-In-Cross-Flow with turbulent inflow generation

Abstract

Hot jets-in-cross-flow are frequently encountered in aeronautics and the accurate estimation of the wall temperature in the jet wake is crucial during the early design of a new aircraft. However, common two-equation RANS models fail at estimating the wall temperature in the jet wake. The use of Large-Eddy Simulation, which seems to be a promising solution at first sight, is not applicable due to its prohibitive computational cost on such large Reynolds number wall-bounded flows. For an affordable cost, we propose a strategy which consists in: reducing the computational domain to a small region around the phenomenon of interest (RANS-LES embedded approach), perform a Wall-Modelled Large-Eddy Simulation (WMLES) in the reduced domain and generate a turbulent inflow at the reduced domain inlet. The test case selected is a hot Jet-In-Cross-Flow experimentally studied by Albugues (2005) [1]. We simulate the real geometry of the wind-tunnel model, which imposes strong constraints on the inflow generation and numerical method. It is shown that an advanced inflow generation, combining a stochastic velocity fluctuation injection and a dynamic forcing term (Laraufie et al., 2011) [17], is mandatory to obtain a realistic turbulent flow upstream of the jet. In the jet wake, the wall temperature estimated by the WMLES agrees well with the experimental measurements.