The wall treatment for omega in the k-omega turbulence model has been improved to be less sensitive to the near-wall mesh resolution than in previous FLUENT versions. The previous treatment method can be recovered with the rpvar setting “(rpsetvar 'kw-wall-omega-treatment-r13? #f)”

More realistic (non-constant) epsilon and omega fields are now used for initialization when the turbulence model is changed between k-omega and k-epsilon to improve convergence at restart

The use of the PDF and Turbulent Schmidt numbers (Sc) in FLUENT’s partially premixed combustion model has changed from previous FLUENT releases. The table below describes the assignment of these variables to the model’s mixture fraction and reaction progress equations for the current and previous releases. (CL71141)

The PDF Schmidt number is set in the Viscous Model dialog box (default = 0.85) and the Turbulent Schmidt number is set in the Species Model dialog box (default = 0.70)

The Surface-to-surface (S2S) radiation model GUI panel is improved for usability through more clearly labeled settings and more intuitive organization. Additionally, defaults have been updated to correspond to current best-practices, and options that are not generally recommended are no longer present in the GUI.

The default view factor computation method for the surface-to-surface radiation model has been changed from the hemicube method to the ray tracing method

The default number of sub-divisions for the hemicube view factor computation method has been changed from 10 to 5

The Adaptive view factor computation method has been removed from the GUI as an option for the Surface-to-surface radiation model

Least squares smoothing has been removed from the GUI as a view factor calculation option for the Surface-to-surface radiation model

The smooth option has been removed from the Surface-to-surface radiation model

The default value for the maximum number of radiation iterations for the DTRM and Surface-to-surface radiation models has been changed from 10 to 5

The determination of the collision volume for discrete phase particles has been modified for 2d axi-symmetric cases when the spray collision/coalescence model is used. (CL71429)

The calculation of mean NOx production rate has been modified in FLUENT 12 and later versions. (CL68308)

The two-competing rates devolatization model has been modified to correct a problem with devolatization at partition boundaries (parallel solver only) (CL71435)

Solid convection can now be modeled using higher order discretization schemes (selected in Solution Methods panel). In previous FLUENT versions solid convection used first order upwind spatial discretization regardless of the discretization scheme selected. (CL70951)

The default droplet material profile for vapor pressure has been changed from constant to piecewise linear. (CL71648)

The improved wall treatment rpvar default for the VOF model has been changed from “true” to “false” following the discovery of several cases showing unphysical results. (CL62137)

Before defining a monitor on an iso-surface that is dependent on solver data (e.g. velocity, pressure, custom field function etc.) the solution must now be initialized first or an error will result. (CL72914)

The cell-based Weighted Sum of Gray Gases model (WSGGM) has been removed from the GUI. This option is still available in Fluent 13 as a TUI-only feature.

The boiling temperature and latent heat property inputs were unnecessary when defining a real gas equation of state with the DPM model and have been removed.

The method 1 TUI option for target mass flow rate has been removed since the method 2 option covers all cases. Method 1 is still available as an rpvar controlled option.

The Zimont model has been renamed the C-equation model in FLUENT 13.0.

Improvements have been made to the vortex method for applying turbulence boundary conditions for Large Eddy Simulations. Results may vary from previous releases.

The TUI command Use max cell edge for LES length scale? has been removed and is now only available via the rpvar des-maxedge?