The following recommendations appear under the Models tab (Figure 25.21.4):
The realizable - model is a more recent development of the standard - model and differs from it in that the realizable - model contains a new formulation for the turbulent viscosity, as well as a new transport equation for the dissipation rate, , derived from an exact equation for the transport of the mean-square vorticity fluctuation.
realizable - model means that the model satisfies certain mathematical constraints on the Reynolds stresses, consistent with the physics of turbulent flows. For more information on the standard - model and the realizable - model, visit Section 12.4.1 and Section 12.4.3, respectively.
Define Models Viscous...
For information on all - model options, go to Section 12.4.
If you have created a mixing plane, set the Under-Relaxation in the Mixing Plane panel to 1. Look under Global Parameters in Section 10.10.2 for information about the mixing plane under-relaxation.
Define Mixing Planes...
When your case involves the use of dynamic meshes and remeshing is enabled, then it is recommended that you also perform smoothing on the mesh. For a complete discussion of smoothing and remeshing, see Section 11.7.1.
Define Dynamic Mesh Parameters...
By default, FLUENT includes the diffusion flux of species at inlets. In some cases involving species transport and laminar flow, it is recommended that the Inlet Diffusion option in the Species Model panel is disabled. For example,
Define Models Species Transport & Reaction...
For more information about diffusion at inlets, go to Section 14.1.5.
When running thermal NOx simulations and your flow is turbulent, then be sure to set the NOx Turbulence Interaction Mode.
Define Models Species NOx...
In turbulent combustion calculations, FLUENT solves the density-weighted time-averaged Navier-Stokes equations for temperature, velocity, and species concentrations or mean mixture fraction and variance. Methods of modeling the mean turbulent reaction rate can be based on either moment methods or probability density function (PDF) techniques. FLUENT uses the PDF approach.