The LES RBVM (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 using the residual-based variational multiscale (RBVM) method. The equations solved by the LES RBVM interface are the continuity equation for conservation of mass and the Navier–Stokes equation, augmented by additional stress terms, for conservation of momentum. Consistent modeling is used for the additional stresses. The interface is thus also applicable to laminar and transitional flows.

The LES RBVM 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.

A different LES model can be selected under LES model. A RANS turbulence model can be selected by changing the Turbulence model type to RANS, and a DES model can be selected by changing the Turbulence model type to DES. 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.

The LES RBVM 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.

Select this check box to edit the L-VEL wall-treatment parameters, κl and El, and the turbulence model parameter, Cμ, for the Include synthetic turbulence option in the Velocity inlet condition. 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.

To enable this section, click the Show More Options button () and select Stabilization in the Show More Options dialog box.

The Use dynamic subgrid time scale check box is not selected by default.

Select the Limit small time steps effect on stabilization time scale check box to prevent loss of stabilization at small time steps. This check box is selected by default.