Wall-layer models for large-eddy simulations

Because the cost of large-eddy simulations (LES) of wall-bounded flows that resolve all the important eddies depends strongly on the Reynolds number, methods to bypass the wall layer are required to perform high-Reynolds-number LES at a reasonable cost. In this paper the available methodologies are reviewed, and their ranges of applicability are highlighted. Various unresolved issues in wall-layer modeling are presented, mostly in the context of engineering applications.