Adaptive Wall Function for the Prediction of Turbulent Flows

Abstract

Conventionally, two types of wall boundary condition are available for the solution of turbulence transport equations in CFD. These exhibit very different requirements on the wall normal distance of the first grid point and any violation of these requirements leads to a drastic degeneration in the solution quality. This places a very high level of importance on the design of the numerical grid, and contributes to the excessive human resources typically spent on this task. Furthermore, these criteria depend strongly on the local flow field quantities, which means that prior knowledge of the solution is required for correct grid design. In practice this often means that an iterative grid design process is required, causing further grid generation expenditure.