TURBULENCE_MODEL_PARAMETERS

Specifies constants and parameters for turbulence models.

Type

AcuSolve Command

Syntax

TURBULENCE_MODEL_PARAMETERS {parameters...}

Qualifier

This command has no qualifier.

Parameters

spalart_allmaras_cb1 (real) >=0 [=0.1355]

Spalart-Allmaras model constant.

spalart_allmaras_cb2 (real) >=0 [=0.622]

Spalart-Allmaras model constant.

spalart_allmaras_sigma (real) >=0 [=0.66666666667]

Spalart-Allmaras model constant.

spalart_allmaras_cw1 (real) >=0 [=3.23906781678]

Spalart-Allmaras model constant.

spalart_allmaras_cw2 (real) >=0 [=0.3]

Spalart-Allmaras model constant.

spalart_allmaras_cw3 (real) >=0 [=2]

Spalart-Allmaras model constant.

spalart_allmaras_cv1 (real) >=0 [=7.1]

Spalart-Allmaras model constant.

spalart_allmaras_rotation_curvature (boolean) [=on]

Turn on/off rotation-curvature correction (SA-RC).

spalart_allmaras_cr1 (real) >=0 [=1]

Spalart-Allmaras rotation-curvature correction (SA-RC) constant.

spalart_allmaras_cr2 (real) >=0 [=12]

Spalart-Allmaras rotation-curvature correction (SA-RC) constant.

spalart_allmaras_cr3 (real) >=0 [=1]

Spalart-Allmaras rotation-curvature correction (SA-RC) constant.

spalart_allmaras_qcr (boolean) [=off]

Turn on/off Spalart-Allmaras Quadratic Constitutive Relation (SA-RC) model.

spalart_allmaras_qcr_cr1 (real) >=0 [=0.3]

Spalart-Allmaras Quadratic Constitutive Relation (SA-RC) constant.

spalart_allmaras_qcr_cr2 (real) >=0 [=2.5]

Spalart-Allmaras Quadratic Constitutive Relation (SA-QCR) constant.

spalart_allmaras_des_type (enumerated) [=ddes]

Spalart-Allmaras Detached Eddy Simulation (SA-DES) model type.

des97: Spalart's Detached Eddy Simulation model.
ddes: Delayed DES model.
iddes: Improved Delayed DES (IDDES) model.

spalart_allmaras_des_constant (real) >=0 [=0.25]

SA-DES model constant applicable to des97 and ddes model types.

spalart_allmaras_iddes_cl >=0 [=3.55] (real)

SA-IDDES model constant.

spalart_allmaras_iddes_ct >=0 [=1.63] (real)

SA-IDDES model constant.

spalart_allmaras_iddes_cw (real) >=0 [=0.15]

SA-IDDES model constant.

sst_a1 (real) >=0 [=0.31]

Shear-Stress Transport (SST) model constant.

sst_betastar (real) >=0 [=0.09]

SST model constant.

sst_sigmak1 (real) >=0 [=0.85]

SST model constant.

sst_sigmak2 (real) >=0 [=1]

SST model constant.

sst_sigmao1 (real) >=0 [=0.5]

SST model constant.

sst_sigmao2 (real) >=0 [=0.856]

SST model constant.

sst_beta1 (real) >=0 [=0.075]

SST model constant.

sst_beta2 (real) >=0 [=0.0828]

SST model constant.

sst_gamma1 (real) >=0 [=0.55555555556]

SST model constant.

sst_gamma2 (real) >=0 [=0.44]

SST model constant.

sst_des_constant_1 (real) >=0 [=0.78]

SST-DES model constant.

sst_des_constant_2 (real) >=0 [=0.61]

SST-DES model constant.

sst_production_type (enumerated) [=sst_2003]

SST Production term type.

sst_2003: SST model based on Menter et al., 2003.

sst_rotation_curvature (boolean) [=off]

Turn on/off rotation curvature correction for SST model.

sst_des_type (enumerated) [=ddes]

SST DES model type.

zonal: Zonal DES model.
ddes: Delayed DES model.
iddes: Improved Delayed DES (IDDES) model.

sst_wall_function_type (enumerated) [=all_yplus]

Wall function type.

all_yplus: Wall y+ independent wall function.

k_epsilon_cmu (real) >=0 [=0.09]

Standard K-Epsilon model constant.

k_epsilon_ce1 (real) >=0 [=1.44]

Standard K-Epsilon model constant.

k_epsilon_ce2 (real) >=0 [=1.92]

Standard K-Epsilon model constant.

k_epsilon_sigmak (real) >=0 [=1]

Standard K-Epsilon model constant.

k_epsilon_sigmae (real) >=0 [=1.3]

Standard K-Epsilon model constant.

rng_k_epsilon_cmu (real) >=0 [=0.0845]

ReNormalization Group (RNG) K-Epsilon model constant.

rng_k_epsilon_ce1 (real) >=0 [=1.42]

RNG K-Epsilon model constant.

rng_k_epsilon_ce2 (real) >=0 [=1.92]

RNG K-Epsilon model constant.

rng_k_epsilon_sigmak (real) >=0 [=0.7194]

RNG K-Epsilon model constant.

rng_k_epsilon_sigmae (real) >=0 [=0.7194]

RNG K-Epsilon model constant.

rng_k_epsilon_eta0 (real) >=0 [=4.38]

RNG K-Epsilon model constant.

rng_k_epsilon_beta (real) >=0 [=0.012]

RNG K-Epsilon model constant.

Realizable_k_epsilon_ce1 (real) >=0 [=0.43]

Realizable K-Epsilon model constant.

Realizable_k_epsilon_ce2 (real) >=0 [=1.9]

Realizable K-Epsilon model constant.

Realizable_k_epsilon_sigmak (real) >=0 [=1]

Realizable K-Epsilon model constant.

Realizable_k_epsilon_sigmae (real) >=0 [=1.2]

Realizable K-Epsilon model constant.

Realizable_k_epsilon_eta0 (real) >=0 [=5]

Realizable K-Epsilon model constant.

Realizable_k_epsilon_a0 (real) >=0 [=4.04]

Realizable K-Epsilon model constant.

k_epsilon_twolayer_restar (real) >=0 [=200]

K-Epsilon two-layer wall-function model constant controlling blending layer location.

k_epsilon_twolayer_redelta (real) >=0 [=20]

K-Epsilon two-layer wall-function model constant controlling blending thickness.

k_epsilon_wall_function_type (enumerated) (=two_layer)

Wall function type.

standard: Standard wall-function with first-layer y+ in the log-layer only.
two_layer: Wolfstein two-layer wall-function with all y+ first-layer height.

k_epsilon_realizability_constraint boolean [=on]

Turn on/off Durbin's realizability constraint. Corrects the stagnation point anomaly and improves robustness.

k_omega_alpha (real) >=0 [=0.52]

Wilcox k-omega model constant.

k_omega_betao (real) >=0 [=0.0708]

Wilcox k-omega model constant.

k_omega_clim (real) >=0 [=0.875]

Wilcox k-omega model constant.

k_omega_sigmak (real) >=0 [=0.6]

Wilcox k-omega model constant.

k_omega_sigmao (real) >=0 [=0.5]

Wilcox k-omega model constant.

k_omega_sigmado (real) >=0 [=0.125]

Wilcox k-omega model constant.

k_omega_rotation_curvature (boolean) [=off]

Turn on/off rotation-curvature correction for Wilcox k-omega model.

k_omega_des_constant (real) >=0 [=0.61]

K-omega DES model constants.

bsl_betastar (real) >=0 [=0.09]

Menter's baseline (BSL) K-omega model constant.

bsl_sigmak1 (real) >=0 [=0.5]

BSL K-omega model constant.

bsl_sigmak2 (real) >=0 [=1]

BSL K-omega model constant.

bsl_sigmao1 (real) >=0 [=0.5]

BSL K-omega model constant.

bsl_sigmao2 (real) >=0 [=0.856]

BSL K-omega model constant.

bsl_beta1 (real) >=0 [=0.075]

BSL K-omega model constant.

bsl_beta2 (real) >=0 [=0.0828]

BSL K-omega model constant.

bsl_gamma1 (real) >=0 [=0.55555555556]

BSL K-omega model constant.

bsl_gamma2 (real) >=0 [=0.44]

BSL K-omega model constant.

smagorinsky_constant (real) >=0 [=0.04]

Smagorinsky constant used in Large Eddy Simulation (LES) model.

dynamic_subgrid_model_type (enumerated) [=mij]

Dynamic Subgrid Model type.

kolmogorov: Kolmogorov model.
mij: Mij model.

synthetic_turbulence_input_type or synles (enumerated) (=none)

Large Eddy Simulation (LES) synthetic turbulence inflow type.

none: Deactivate synthetic turbulence flow.
k_omega: Provide k profiles and omega profiles at synthetic inflow.
k_epsilon: Provide k profiles and epsilon profiles at synthetic inflow.

htc_method or htc (enumerated) (=turbulence_wall)

This parameter defines the method used to calculate convective heat transfer coefficient (htc) or surface_film_coefficient.

user_ref_temperature: Calculates the heat transfer coefficient using a user-specified constant reference temperature. The reference temperature is provided by user_reference_temperature. This option requires user_reference_temperature and htc_limit_reference_temp.
direct: Calculates the heat transfer coefficient by evaluating the nodal temperature at the surface and at a specified distance from the surface. This option utilizes film_coefficient_yplus to determine the location within the domain for evaluating the reference temperature. This option requires film_coefficient_yplus and htc_limit_reference_temp.
turbulence_wall: Utilizes the thermal wall function to determine the surface film coefficient. This option requires film_coefficient_yplus and htc_limit_reference_temp.

user_reference_temperature or user_ref_temp (real) > 0 [=300.0]

User-provided reference temperature. Used with htc_method = user_ref_temperature.

htc_limit_reference_temp or htc_ref_limit (boolean) [=on]

Flag specifying whether the reference temperature should be limited to the minimum or maximum values present in the nodal solution. Used with htc_method = user_ref_temperature or htc_method = direct or htc_method = turbulence_wall.

film_coefficient_yplus (real) > 0 [=100]

Value of y+ used to evaluate non-dimensional temperature in surface_film_coefficient. Used with htc_method = direct or htc_method = turbulence_wall.

von_karman_constant (real) >=0 [=0.41]

Von Kármán constant used in logarithmic law describing a turbulent boundary layer's velocity profile.

intermittency_ctu1 (real) [=100]

Intermittency equation constant for Gamma transition model.

intermittency_ctu2 (real) [=1000]

Intermittency equation constant for Gamma transition model.

intermittency_ctu3 (real) [=1]

Intermittency equation constant for Gamma transition model.

intermittency_cpg1 (real) [=14.68]

Intermittency equation constant for Gamma transition model.

intermittency_cpg2 (real) [=-7.34]

Intermittency equation constant for Gamma transition model.

intermittency_cpg3 (real) [=0]

Intermittency equation constant for Gamma transition model.

retheta_critical_type (enumerated) [=default]

Critical Re-Theta correlation type.

default: Default value.
user_function: User-defined function.

retheta_critical_user_function (string) [=]

Name of the user-defined function. Used when retheta_critical_type = user_function.

retheta_critical_user_values (array) [={ }]

Array of values to be passed to the user-defined function. Used with retheta_critical_user_function type.

retheta_critical_user_strings (array) [={ }]

Array of strings to be passed to the user-defined function. Used with retheta_critical_user_function type.

flength_type (enumerated) [=default]

F-Length correlation type.

default: Default value.
user_function: User-defined function.

flength_user_function (string) [=]

Name of the user-defined function. Used when flength_type = user_function.

flength_user_values (array) [={ }]

Array of values to be passed to the user-defined function. Used with flength_user_function type.

flength_user_strings (array) [={ }]

Array of strings to be passed to the user-defined function. Used with flength_user_function type.

Description

This command modifies the turbulence model constants and parameters to the user desired quantity or option from the default selection. For example,

TURBULENCE_MODEL_PARAMETERS {
    k_epsilon_cmu = 0.1
}

modifies the standard k-epsilon turbulence model constant c $μ$ from its default value of 0.09 to 0.1.

Similarly, for Boolean options, example:

TURBULENCE_MODEL_PARAMETERS {
    sst_rotation_curvature = on
}

turns on rotation-curvature correction for the SST model.

The synthetic turbulence feature accepts two types of inflow profiles: K-Omega and K-Epsilon. For example,

TURBULENCE_MODEL_PARAMETERS {
    Synthetic_turbulence_input_type = k_omega
}

This command is only active when large_eddy_simulation or dynamic_model is chosen at the turbulence command and inflow type is set to velocity or atmospheric. If the k_omega option is set, then corresponding turbulent kinetic energy and turbulent eddy frequency profiles (or values) need to be specified at inflow to generate synthetic turbulence. If k-epsilon is chosen, then turbulent kinetic energy and turbulent dissipation rate profiles (or values) are required to be set at inflow.

htc_method provides three options to compute the Heat Transfer Coefficient (HTC).

TURBULENCE_MODEL_PARAMETERS {
    htc_method = user_ref_temperature
    htc_limit_reference_temp = on
    user_reference_temperature = 300
}

When htc_method is set to user_ref_temperature, AcuSolve calculates the heat transfer coefficient using a user-specified constant reference temperature, denoted as user_reference_temperature. Additionally, htc_limit_reference_temp determines whether the reference temperature should be limited to the minimum or maximum values present in the nodal, ensuring that the heat transfer coefficient (surface_filim_coefficient) remains positive.

{htc}_{1} = q / (T_{r e f} - T_{w a l l})

where

q

is the local surface heat flux,

T_{w a l l}

is the local wall temperature,

T_{r e f}

is the user-specified reference temperature (must be smaller than the minimum of local wall temperature (

T_{w a l l}

TURBULENCE_MODEL_PARAMETERS {
    htc_method = direct
    htc_limit_reference_temp = on
    film_coefficient_yplus = 100
}

When htc_method is set to direct, AcuSolve calculates the heat transfer coefficient by evaluating the nodal temperature at the surface and at a specified distance away from the surface. This method utilizes film_coefficient_yplus to determine the location where the reference temperature is evaluated. Additionally, the htc_limit_reference_temp option specifies whether the reference temperature should be constrained to the minimum or maximum values present in the nodal solution, ensuring that the heat transfer coefficient (surface_filim_coefficient) remains positive.

{htc}_{2} = q / (T_{ref_local} - T_{w a l l})

where

T_{ref_local}

is the local reference temperature at user-specified yplus film_coefficient_yplus.

TURBULENCE_MODEL_PARAMETERS {
    htc_method = turbulence_wall
    htc_limit_reference_temp = on
    film_coefficient_yplus = 100
}

When htc_method is set to turbulence_wall, AcuSolve uses film_coefficient_yplus to calculate the surface film coefficient (heat transfer coefficient) by applying the thermal wall function. Additionally, the htc_limit_reference_temp option specifies whether the reference temperature should be constrained to the minimum or maximum values present in the nodal solution, ensuring that the heat transfer coefficient (surface_filim_coefficient) remains positive.

{htc}_{3} = (ρ C_{p} ​ U_{τ}) / T^{+}

where $ρ$ is the local density, $C_{p}$ is the local specific heat, $U_{τ} = \sqrt{\frac{τ_{wall}}{ρ}}$ is the local friction velocity (wall shear stress divided by density). $T^{+}$ is the non-dimensional temperature.

AcuSolve thermal wall function is

T^{+} = \Pr y^{+} e^{- L} + (2.12 \ln (1 + y^{+}) + β) e^{- 1 / L}

where $L = \frac{0.01 {(\Pr y^{+})}^{4}}{1 + 5 \Pr^{3} y^{+}}$

β = {(3.85 \Pr^{1 / 3} - 1.3)}^{2} + 2.12 \ln (\Pr)

$\Pr = \frac{μ C_{p}}{k}$ the local Prandtl number (Pr) is a function of viscosity $μ$ , specific heat capacity $C_{p}$ , and conductivity $k$ .

$T^{+} = \frac{T_{w} - T}{T^{*}}$ non-dimensional temperature.

T_{w}

is the wall temperature,

T^{*} = q / (ρ C_{p} ​ u^{*})

is the friction temperature.

Note: When using the htc methods direct or user_ref_temperature, AcuTherm will print the results corresponding to direct or user_ref_temperature, rather than turb_wall. It is essential to ensure that turb_wall is selected for htc_method to ensure that AcuTherm prints the correct values.