Enhanced Delayed DES of shock wave/boundary layer interaction in a planar transonic nozzle

摘要

Delayed detached-eddy simulations of a Shock Wave/Boundary-Layer Interaction (SWBLI) in an over-expanded transonic nozzle have been carried out to evaluate the performance of different subgrid lengthscales Δ on the computed results. In particular an enhanced DDES is carried out by exploting the Shear Layer Adapted (SLA) subgrid lengthscale Δ_(SLA)* recently introduced by Shur et al. [2015] to drastically reduce the turbulent viscosity in the quasi-2D flow regions. Our results show that the enhanced DDES is effective in promoting a faster development of instabilities in the detaching shear-layer, providing improved predictions in terms of mean wall pressure distribution, velocity profiles and frequency of the shock motion with respect to DDES computations performed with classical subgrid lenghtscales.