### 2.7.2. Wall Roughness

For simulations using turbulence models, you can describe the wall surface as being smooth or rough. For rough walls, the equivalent sand-grain roughness is required as input parameter. An additional modeling option, `High Roughness (Icing)`, is available when using the SST turbulence model. The details of the rough wall treatment for turbulence models based on the and – equation can be found in Treatment of Rough Walls in the CFX-Solver Theory Guide.

This option is not available for the `Free Slip` wall boundary condition, or when a turbulence model is not used (that is, Laminar).

Release 18.2 - © ANSYS, Inc. All rights reserved.