In the Vreman model [15], the eddy viscosity is modeled by:
 | (10–8) |
where
 | (10–9) |
 | (10–10) |
 | (10–11) |
is the filtered velocity, 
is a model constant with the default value of 0.072. Note that the isotropic
form of the model is implemented in Fluent, that is, the filter width is considered to be the
same in each direction (
).
The grid-scale 
is computed as follows:
 | (10–12) |
where 
is the wall distance and 
is the volume of the computational cell.
Unlike the Smagorinsky model, the Vreman model ensures zero eddy-viscosity in pure laminar shear flows.
The Vreman model is available after enabling beta feature access, as described in Introduction.
The Vreman model option is available under Subgrid-Scale Model, as
shown in Figure 10.6: The Viscous Model Dialog Box with Vreman Model Enabled after selecting Large Eddy Simulation
(LES). Under Model Constants, you are able to modify the value
for 
.
You can also enable the model using the TUI command:
define/models/viscous/les-subgrid-vreman?
The model constant can be specified using the TUI command:
define/models/viscous/les-model-options/cvreman