OpenFOAM Tutorial | pitzDaily | LES Turbulence Model
Written by cfd.ninja
The incompressible and compressible RAS turbulence models, isochoric and anisochoric LES models and delta models are all named and described in Table A.5. Examples of their use can be found in the $FOAM_TUTORIALS.
5.3.1 Model coefficients
The coefficients for the RAS turbulence models are given default values in their respective source code. If the user wishes to override these default values, then they can do so by adding a sub-dictionary entry to the RAS dictionary, whose keyword name is that of the model with Coeffs appended, e.g. kEpsilonCoeffs for the kEpsilon model. If the printCoeffs switch is on an example of the relevant …Coeffs dictionary is printed to standard output when the model is created at the beginning of a run. The user can simply copy this into the RAS dictionary and edit the entries as required.
5.3.2 Wall functions
A range of wall function models is available in OpenFOAM that are applied as boundary conditions on individual patches. This enables different wall function models to be applied to different wall regions. The choice of wall function model is specified through in the 0/nut file. For example, a 0/nut file:
18dimensions [0 2 -1 0 0 0 0];
19
20internalField uniform 0;
21
22boundaryField
23{
24 movingWall
25 {
26 type nutkWallFunction;
27 value uniform 0;
28 }
29 fixedWalls
30 {
31 type nutkWallFunction;
32 value uniform 0;
33 }
34 frontAndBack
35 {
36 type empty;
37 }
38}
39
40
41// ************************************************************************* //
There are a number of wall function models available in the release, e.g. nutkWallFunction, nutUWallFunction, nutUSpaldingWallFunction. The user can consult the relevant directories for a full list of wall function models:
In this tutorial, you will learn how simulate a LES Turbulence Model using OpenFOAM.
