A wall-modeled/wall-resolved les method for turbulent wall flows

Abstract

This present paper reports a novel methodology to simulate wall-bounded flows in the LargeEddy Simulation framework using an automatic transition between a wall-modelled and a wall-resolved approach. The proposed technique aims at prescribing the right (modelled or resolved) wall shear stress and wall heat flux, preserving at the same time the no-slip/no-penetration conditions for the velocity and the isothermal/adiabatic conditions for the temperature fields. The approach is successfully implemented in a high-order finite-difference framework, and it is found able to adapt smoothly to the available nearwall grid spacing. Thus, the method falls into the wall-resolved case, when the near-wall dynamic is directly computed, whereas it employs the wall stress model when a full resolution of the near-wall region is not achievable. The method is tested on a nearly-incompressible turbulent channel flow and a supersonic spatially-devolving boundary layer flow. The obtained results highlight an excellent accuracy in representing the wall turbulence dynamics in terms of mean velocity profiles and fluctuations, almost independently of the near-wall spatial resolution. Thus, the proposed method results in a promising technique for analysis of high-Reynolds wall-bounded flows.