This paper addresses one of the most persistent errors in wall-modeled large eddy simulation: the inevitable presence of numerical and subgrid modeling errors in the first few grid points off the wall, which leads to the so-called “log-layer mismatch” with its associated 10-15% error in the predicted skin friction. By considering the behavior of turbulence length scales near a wall, the source of these errors is analyzed, and a method that allows for the log-layer mismatch to be removed, thereby yielding accurately predicted skin friction, is proposed.

The paper provides a brief introduction to the near-wall problem of LES and how it can be solved through modeling of the near-wall turbulence. The distinctions and key differences between different approaches are emphasized, both in terms of fidelity (LES, wall-modeled LES, and DES) and in terms of different wall-modeled LES approaches (hybrid LES/RANS and wall-stress-models). The focus is on approaches that model the wall-stress directly, i.e., methods for which the LES equations are formally solved all the way down to the wall. Progress over the last decade is reviewed, and the most important and promising directions for future research are discussed.

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