The LES RBVMWV Interface
The LES RBVMWV (spf) interface () is used for simulating single-phase flows at high Reynolds numbers by resolving the larger three-dimensional unsteady eddies and modeling the effect of the smaller eddies. The physics interface is currently only suitable for incompressible flows.
The equations solved by the LES RBVMWV interface are the continuity equation for conservation of mass and the Navier–Stokes equation, augmented by additional stress terms, for conservation of momentum. Similar modeling as for the LES RBVM model is applied but the effect of the Reynolds stress is enhanced by adding a turbulent viscosity term. Since the modeling is consistent, the interface is also applicable to laminar and transitional flows.
The LES RBVMWV interface should only be used for three-dimensional, time-dependent analyses. The main feature is Fluid Properties, which adds the Navier–Stokes and continuity equations, and provides an interface for defining the fluid material and its properties. When this physics interface is added, the following default nodes are also added in the Model Builder: Fluid Properties, Initial Values, and Wall.
Except where included below, see The Laminar Flow Interface for all the other settings.
Turbulence
A different LES model can be selected under Turbulence model. A RANS turbulence model can be selected by changing the Turbulence model type to RANS. Laminar or creeping flow may be simulated by changing the Turbulence model type to None.
The Turbulence model property disables the Neglect inertial term (Stokes flow) check box and Enable porous media domains check box.
Wall Treatment
The LES RBVMWV model employs per default a Low Re wall treatment, which applies a Dirichlet condition for the velocity field.
Select the Automatic option in order to apply a tangential-stress condition based on a blending of asymptotic expressions in the viscous wall layer and the log layer. The automatic wall treatment gives a robust formulation that makes the most out of the available resolution.
Edit LES Model Parameters
Select this check box to edit the L-VEL wall-treatment parameters, κl and El, and the turbulent viscosity parameter . Turbulence model parameters are optimized to fit as many flow types as possible, but for some special cases, better performance can be obtained by tuning the model parameters.
Consistent Stabilization
To enable this section, click the Show More Options button () and select Stabilization in the Show More Options dialog box.
Select the Use dynamic subgrid time scale check box to use the time derivative from the previous time step to estimate temporal changes in the unresolved scales.
Dependent Variables
The following dependent variables (fields) are defined for this physics interface:
Velocity field u and its components