A constraint for the subgrid-scale stresses in the logarithmic region of high Reynolds number turbulent boundary layers: A solution to the log-layer mismatch problem

摘要

This paper addresses one of the most persisting problems in wall-modeled large eddy simulation (LES): the overshoot of the mean velocity gradient near the wall, often referred to as the “log-layer mismatch” problem. An analysis of the relationship between turbulent kinetic energy budgets and mean velocity gradient is elaborated for both direct numerical simulations and LES of fully developed channel flow at high Reynolds number. Based on the analysis, a self-adaptive Smagorinsky model for LES of high-Reynolds-number boundary layer flows is proposed, in which the Smagorinsky coefficient is dynamically adjusted so that a logarithmic mean velocity distribution is captured. The model is then implemented in a second-order finite-volumecode, and applied to a high-Reynolds-number channel flow with rough walls. We find that the desired logarithmic mean velocity distribution is well predicted for different resolutions and grid aspect ratios.