wall
Wall boundary condition.
Mesh zone ids this boundary condition applies to.
Guidance: Choosing boundary conditions →Wall model applied on these zones.
| Value | What it does | When to use it |
|---|---|---|
| slip | Zero velocity normal to the wall and no shear stress along it. | |
| no slip default | Applies the no-slip condition directly at the wall. | Viscous wall with the mesh resolved to . |
| wall function | Takes the wall stress from a law of the wall instead of resolving the near-wall layer: Spalding's law with SST, the Allmaras fit with SA-neg. | Viscous wall with the first cell between and ; it tolerates a first cell down to . The law of the wall (Spalding's with SST, the Allmaras fit with SA-neg) represents a flat plate in zero pressure gradient, so accuracy falls on highly curved surfaces and in strong pressure gradients. |
| most | Takes the wall stress and surface heat flux from Monin-Obukhov similarity theory on a roughness length. |
Both runs use the Spalart–Allmaras model on meshes with the same number of cells. The wall-function mesh places its first cell a hundred times further from the wall.
Applies the compressible law of the wall on an adiabatic wall-function wall; a 'temperature' or a 'heat flux' selects it anyway.
Both runs are adiabatic at M = 2, with Menter SST and a wall function on the same mesh.