For the LES models, following wall function are available:
Thie widely used blending of the laminar sublayer and logarithmic laws of Kader [286] is the default option in Fluent.
When the mesh is fine enough to resolve the laminar sublayer, the wall shear stress is obtained from the laminar stress-strain relationship:
 | (4–404) |
If the mesh is too coarse to resolve the laminar sublayer, it is assumed that the centroid of the wall-adjacent cell falls within the logarithmic region of the boundary layer, and the law-of-the-wall is employed:
 | (4–405) |
where 
is the von Kármán constant and 
. If the mesh is such that the first near-wall point is within the buffer
region, then two above laws are blended in accordance with Equation 4–369.
Classical law-of-the-wall formulations are of the form:
 | (4–406) |
This equation relates the unknown shear velocity 
with the known quantities of u, y, and ν at the near wall cell center.
To compute 
, iterations are required and the explicit formulation is based on an
alternative variable which does not contain 
:
 | (4–407) |
viscous sub-layer formulation:
 | (4–408) |
log-layer formulation:
 | (4–409) |
with 
=2.21, 
=4.
To blend the viscous sub-layer with the logarithmic layer, the harmonic power law is employed:
 | (4–410) |
with an exponent of 
=6.
Harmonic blending wall functions can be enabled from The Viscous Model Panel (as described in Setting Up the Large Eddy Simulation Model in the Fluent User's Guide) or by using the following text command:
define/models/viscous/near-wall-treatment/harmonic-blend-rplus-wf?
Unlike other Wall Treatment options available for LES, 
-based wall functions support including wall roughness effect (see Wall Roughness Effects in Turbulent Wall-Bounded Flows).
Note: To maintain the full effect of the roughness on the flow when using Harmonic blending wall
functions based on 
in combination with Rough Walls, make sure that the mesh satisfies the
requirements 
.
For the LES simulations in Ansys Fluent, there is an alternative near-wall approach based on the work of Werner and Wengle [702], who proposed an analytical integration of the power-law near-wall velocity distribution resulting in the following expressions for the wall shear stress:
 | (4–411) |
where 
is the wall-parallel velocity, 
are the constants, and 
is the near-wall control volume length scale.
The Werner-Wengle wall functions can be enabled using the
define/models/viscous/near-wall-treatment/werner-wengle-wall-fn? text
command.