Wall-modeled large eddy simulations of a turbulent boundary layer over a bump at Re_L = 1 and 2 million

A turbulent boundary layer involving favorable and adverse pressure gradients and flow separation is encountered in a fluid flow over an aircraft wing at a high angle of attack. For such flows, Reynolds averaged Navier-Stokes (RANS) models are found to be inadequate, and on the other hand performing scale-resolving simulations such as wall-resolved large eddy simulations (WRLES) involves large computational overhead that makes it intractable for large Reynolds numbers. For such industrial flows, the use of hybrid RANS-LES simulations such as IDDES is growing. However, the fidelity of IDDES for such flows is not yet established and we take a step in that direction.

In this talk, we present IDDES results for a turbulent boundary layer flow over Boeing/Gaussian bump at Re_L = 1 and 2 million. The flow involves favorable and adverse pressure gradient regions which eventually leads to flow separation at higher Reynolds numbers. This flow is a challenging problem for existing RANS models as they fail to account for pressure gradient effects or predict flow separation region correctly. We investigate the evolution of velocity and stress profiles along with streamwise directions estimated by IDDES for the two different Reynolds number cases and compare it to RANS and DNS predictions.