Turbulence model tuning coefficients
You can modify the turbulence model constants using the advanced parameters in the user.prm file.
For example, to set the standard σk coefficient to 2.0, add the
following line to the user.prm file using a simple text editor,
which you save in the run directory: SIGMA_K_KEPS_STD = 2.0
For more information on the user.prm file, see Flow solver files.
The following table lists the advanced parameters you use to modify the coefficients in Standard k-epsilon model.
| Advanced parameter | Default | Description |
|---|---|---|
SIGMA_K_KEPS_STD |
1.0 | Sets the σk coefficient. |
SIGMA_EPS_KEPS_STD |
1.3 | Sets the σε coefficient. |
C_MU_KEPS_STD |
0.09 | Sets the Cμ coefficient. |
C_EPSILON1_KEPS_STD |
1.44 | Sets the Cε1 coefficient. |
C_EPSILON2_KEPS_STD |
1.92 | Sets the Cε2 coefficient. |
The following table lists the advanced parameters you use to modify the coefficients in the RNG k-epsilon model.
| Advanced parameter | Default | Description |
|---|---|---|
ALPHA_K_KEPS_RNG |
1.39 | Sets the coefficient α for k equation. |
ALPHA_EPS_KEPS_RNG |
1.39 | Sets the coefficient α for epsilon equation. |
C_MU_KEPS_RNG |
0.0845 | Sets the Cμ coefficient. |
C_EPSILON1_KEPS_RNG |
1.42 | Sets the Cε1 coefficient. |
C_EPSILON2_KEPS_RNG |
1.68 | Sets the Cε2 coefficient. |
ETA0_KEPS_RNG |
4.38 | Sets the η0 coefficient. |
BETA_KEPS_RNG |
0.012 | Sets the β coefficient. |
The following table lists the advanced parameters you use to modify the coefficients in the Realizable k-epsilon model.
| Advanced parameter | Default | Description |
|---|---|---|
SIGMA_K_KEPS_REAL |
1.0 | Sets the σk coefficient. |
SIGMA_EPS_KEPS_REAL |
1.2 | Sets the σεcoefficient. |
C2_KEPS_REAL |
1.9 | Sets the C2 coefficient. |
A0_KEPS_REAL |
4.0 | Sets the A0 coefficient. |
The following table lists the advanced parameters you use to modify the coefficients in the k-omega model.
| Advanced parameter | Default | Description |
|---|---|---|
SIGMA_K_KOMG |
0.5 | Sets the σk coefficient. |
SIGMA_OMG_KOMG |
0.5 | Sets the σω coefficient. |
ALPHA_KOMG |
0.52 | Sets the α coefficient. |
BETA0_KOMG |
0.072 | Sets the β0 coefficient. |
BETA_STAR0_KOMG |
0.09 | Sets the β*0 coefficient. |
The following table lists the advanced parameters you use to modify the coefficients in the Shear stress transport model.
| Advanced parameter | Default | Description |
|---|---|---|
SIGMA_K1_SST |
1.0/0.85 | Sets the σk1 coefficient. |
SIGMA_K2_SST |
1.0 | Sets the σk2 coefficient. |
SIGMA_OMG1_SST |
2.0 | Sets the σω1 coefficient. |
SIGMA_OMG2_SST |
1.0/0.856 | Sets the σω2 coefficient. |
A1_SST |
0.31 | Sets the a1 coefficient. |
ALPHA1_SST |
5.0/9.0 | Sets the α1 coefficient. |
ALPHA2_SST |
0.44 | Sets the α2 coefficient. |
BETA1_SST |
0.075 | Sets the β1 coefficient. |
BETA2_SST |
0.0828 | Sets the β2 coefficient. |
BETA_STAR_SST |
0.09 | Sets the β* coefficient. |
The following table lists the advanced parameters you use to modify the coefficients in the Spalart-Allmaras model.
| Advanced parameter | Default | Description |
|---|---|---|
SIGMA_SA |
2.0/3.0 | Sets the σ coefficient. |
CB1_SA |
0.1355 | Sets the Cb1 coefficient. |
CB2_SA |
0.622 | Sets the Cb2 coefficient. |
KAPPA_SA |
0.41 | Sets the k coefficient. |
C_OMG2_SA |
0.3 | Sets the Cω2 coefficient. |
C_OMG3_SA |
2.0 | Sets the Cω3 coefficient. |
C_V1_SA |
7.1 | Sets the Cv1 coefficient. |