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cs_turbulence_bc.h File Reference
#include "base/cs_defs.h"
Include dependency graph for cs_turbulence_bc.h:

Go to the source code of this file.

Functions

void cs_turbulence_bc_init_pointers (void)
 Initialize turbulence model boundary condition pointers.
void cs_turbulence_bc_free_pointers (void)
 Free memory allocations for turbulence boundary condition pointers.
void cs_turbulence_bc_ke_hyd_diam (double uref2, double dh, double rho, double mu, double *ustar2, double *k, double *eps)
 Calculation of $ u^\star $, $ k $ and $\varepsilon $ from a diameter $ D_H $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall (use for inlet boundary conditions).
void cs_turbulence_bc_ke_turb_intensity (double uref2, double t_intensity, double dh, double *k, double *eps)
 Calculation of $ k $ and $\varepsilon$ from a diameter $ D_H $, a turbulent intensity $ I $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall (for inlet boundary conditions).
void cs_turbulence_bc_inlet_hyd_diam (cs_lnum_t face_id, double uref2, double dh, double rho, double mu)
 Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall.
void cs_turbulence_bc_inlet_turb_intensity (cs_lnum_t face_id, double uref2, double t_intensity, double dh)
 Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $, a turbulent intensity $ I $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall.
void cs_turbulence_bc_inlet_k_eps (cs_lnum_t face_id, double k, double eps)
 Set inlet boundary condition values for turbulence variables based on given k and epsilon values.
void cs_turbulence_bc_set_uninit_inlet (cs_lnum_t face_num, double k, double rij[], double eps)
void cs_turbulence_bc_set_uninit_inlet_hyd_diam (cs_lnum_t face_id, double vel_dir[], double shear_dir[], double uref2, double dh, double rho, double mu)
 Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall, only if not already set.
void cs_turbulence_bc_set_uninit_inlet_turb_intensity (cs_lnum_t face_id, double uref2, double t_intensity, double dh)
 Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $, a turbulent intensity $ I $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall, only if not already set.
void cs_turbulence_bc_set_uninit_inlet_k_eps (cs_lnum_t face_id, double k, double eps, double vel_dir[], double shear_dir[])
 Set inlet boundary condition values for turbulence variables based on given k and epsilon values only if not already initialized.
void cs_turbulence_bc_set_hmg_neumann (cs_lnum_t face_id)
 Assign homogeneous Neumann turbulent boundary conditions to a given face.
void cs_turbulence_bc_rij_transform (int is_sym, cs_real_t p_lg[3][3], cs_real_t alpha[6][6])
 Compute matrix $\tens{\alpha}$ used in the computation of the Reynolds stress tensor boundary conditions.

Function Documentation

◆ cs_turbulence_bc_free_pointers()

void cs_turbulence_bc_free_pointers ( void )

Free memory allocations for turbulence boundary condition pointers.

◆ cs_turbulence_bc_init_pointers()

void cs_turbulence_bc_init_pointers ( void )

Initialize turbulence model boundary condition pointers.

◆ cs_turbulence_bc_inlet_hyd_diam()

void cs_turbulence_bc_inlet_hyd_diam ( cs_lnum_t face_id,
double uref2,
double dh,
double rho,
double mu )

Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall.

We use the laws from Idel'Cik, i.e. the head loss coefficient $ \lambda $ is defined by:

\[ |\dfrac{\Delta P}{\Delta x}| = \dfrac{\lambda}{D_H} \frac{1}{2} \rho U_{ref}^2 \]

then the relation reads $u^\star = U_{ref} \sqrt{\dfrac{\lambda}{8}}$. $\lambda $ depends on the hydraulic Reynolds number $ Re = \dfrac{U_{ref} D_H}{ \nu} $ and is given by:

  • for $ Re < 2000 $

    \[ \lambda = \dfrac{64}{Re} \]

  • for $ Re > 4000 $

    \[ \lambda = \dfrac{1}{( 1.8 \log_{10}(Re)-1.64 )^2} \]

  • for $ 2000 < Re < 4000 $, we complete by a straight line

    \[ \lambda = 0.021377 + 5.3115. 10^{-6} Re \]

From $ u^\star $, we can estimate $ k $ and $ \varepsilon$ from the well known formulae of developped turbulence

Parameters
[in]face_idboundary face id
[in]uref2square of the reference flow velocity
[in]dhhydraulic diameter $ D_H $
[in]rhomass density $ \rho $
[in]mudynamic viscosity $ \nu $

◆ cs_turbulence_bc_inlet_k_eps()

void cs_turbulence_bc_inlet_k_eps ( cs_lnum_t face_id,
double k,
double eps )

Set inlet boundary condition values for turbulence variables based on given k and epsilon values.

Parameters
[in]face_idboundary face id
[in]kturbulent kinetic energy
[in]epsturbulent dissipation

◆ cs_turbulence_bc_inlet_turb_intensity()

void cs_turbulence_bc_inlet_turb_intensity ( cs_lnum_t face_id,
double uref2,
double t_intensity,
double dh )

Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $, a turbulent intensity $ I $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall.

Parameters
[in]face_idboundary face id
[in]uref2square of the reference flow velocity
[in]t_intensityturbulent intensity $ I $
[in]dhhydraulic diameter $ D_H $

◆ cs_turbulence_bc_ke_hyd_diam()

void cs_turbulence_bc_ke_hyd_diam ( double uref2,
double dh,
double rho,
double mu,
double * ustar2,
double * k,
double * eps )

Calculation of $ u^\star $, $ k $ and $\varepsilon $ from a diameter $ D_H $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall (use for inlet boundary conditions).

Both $ u^\star $ and $ (k,\varepsilon )$ are returned, so that the user may compute other values of $ k $ and $ \varepsilon $ with $ u^\star $.

We use the laws from Idel'Cik, i.e. the head loss coefficient $ \lambda $ is defined by:

\[ |\dfrac{\Delta P}{\Delta x}| = \dfrac{\lambda}{D_H} \frac{1}{2} \rho U_{ref}^2 \]

then the relation reads $u^\star = U_{ref} \sqrt{\dfrac{\lambda}{8}}$. $\lambda $ depends on the hydraulic Reynolds number $ Re = \dfrac{U_{ref} D_H}{ \nu} $ and is given by:

  • for $ Re < 2000 $

    \[ \lambda = \dfrac{64}{Re} \]

  • for $ Re > 4000 $

    \[ \lambda = \dfrac{1}{( 1.8 \log_{10}(Re)-1.64 )^2} \]

  • for $ 2000 < Re < 4000 $, we complete by a straight line

    \[ \lambda = 0.021377 + 5.3115. 10^{-6} Re \]

From $ u^\star $, we can estimate $ k $ and $ \varepsilon$ from the well known formulae of developped turbulence

\[ k = \dfrac{u^{\star 2}}{\sqrt{C_\mu}} \]

\[ \varepsilon = \dfrac{ u^{\star 3}}{(\kappa D_H /10)} \]

Parameters
[in]uref2square of the reference flow velocity
[in]dhhydraulic diameter $ D_H $
[in]rhomass density $ \rho $
[in]mudynamic viscosity $ \nu $
[out]ustar2square of friction speed
[out]kcalculated turbulent intensity $ k $
[out]epscalculated turbulent dissipation $ \varepsilon $

◆ cs_turbulence_bc_ke_turb_intensity()

void cs_turbulence_bc_ke_turb_intensity ( double uref2,
double t_intensity,
double dh,
double * k,
double * eps )

Calculation of $ k $ and $\varepsilon$ from a diameter $ D_H $, a turbulent intensity $ I $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall (for inlet boundary conditions).

\[ k = 1.5 I {U_{ref}}^2 \]

\[ \varepsilon = 10 \dfrac{{C_\mu}^{0.75} k^{1.5}}{ \kappa D_H} \]

Parameters
[in]uref2square of the reference flow velocity
[in]t_intensityturbulent intensity $ I $
[in]dhhydraulic diameter $ D_H $
[out]kcalculated turbulent intensity $ k $
[out]epscalculated turbulent dissipation $ \varepsilon $

◆ cs_turbulence_bc_rij_transform()

void cs_turbulence_bc_rij_transform ( int is_sym,
cs_real_t p_lg[3][3],
cs_real_t alpha[6][6] )

Compute matrix $\tens{\alpha}$ used in the computation of the Reynolds stress tensor boundary conditions.

We note $\tens{R}_g$ the Reynolds Stress tensor in the global reference frame (mesh reference frame) and $\tens{R}_l$ the Reynolds stress tensor in the local reference frame (reference frame associated to the boundary face).

$\tens{P}_{lg}$ is the change of basis orthogonal matrix from local to global reference frame.

$\tens{\alpha}$ is a 6 by 6 matrix defined such that:

\[\vect{R}_{g,\fib} = \tens{\alpha} \vect{R}_{g,\centip} + \vect{R}_{g}^* \]

where symetric tensors $\tens{R}_g$ have been unfolded as follows:

\[\vect{R}_g = \transpose{\left(R_{g,11},R_{g,22},R_{g,33}, R_{g,12},R_{g,13},R_{g,23}\right)} \]

.

$ \tens{R}_{g,\fib} $ should be computed as a function of $\tens{R}_{g,\centip}$ as follows:

\[\tens{R}_{g,\fib}=\tens{P}_{lg}\tens{R}_{l,\fib}\transpose{\tens{P}_{lg}} \]

with

\[\tens{R}_{l,\fib} = \begin{bmatrix} R_{l,11,\centip} & 0 & c R_{l,13,\centip}\\ 0 & R_{l,22,\centip} & 0 \\ c R_{l,13,\centip} & 0 & R_{l,33,\centip} \end{bmatrix} + \underbrace{\begin{bmatrix} 0 & (1-c) u^* u_k & 0 \\ (1-c) u^* u_k & 0 & 0 \\ 0 & 0 & 0 \end{bmatrix}}_{\vect{R}_l^*} \]

and $\tens{R}_{l,\centip}=\transpose{\tens{P}_{lg}}\tens{R}_{g,\centip} \tens{P}_{lg}$.

Constant c is chosen depending on the type of the boundary face: $c = 0$ at a wall face, $c = 1$ at a symmetry face.

Parameters
[in]is_symConstant c in description above (1 at a symmetry face, 0 at a wall face)
[in]p_lgchange of basis matrix (local to global)
[out]alphatransformation matrix

◆ cs_turbulence_bc_set_hmg_neumann()

void cs_turbulence_bc_set_hmg_neumann ( cs_lnum_t face_id)

Assign homogeneous Neumann turbulent boundary conditions to a given face.

This is useful for outgoing flow.

◆ cs_turbulence_bc_set_uninit_inlet()

void cs_turbulence_bc_set_uninit_inlet ( cs_lnum_t face_num,
double k,
double rij[],
double eps )

◆ cs_turbulence_bc_set_uninit_inlet_hyd_diam()

void cs_turbulence_bc_set_uninit_inlet_hyd_diam ( cs_lnum_t face_id,
double vel_dir[],
double shear_dir[],
double uref2,
double dh,
double rho,
double mu )

Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall, only if not already set.

Apart from assigning values where not already initialized, this function is similar to cs_turbulence_bc_inlet_hyd_diam.

Parameters
[in]face_idboundary face id
[in]vel_dirvelocity direction (not normalized, or nullptr)
[in]shear_dirshear direction (or nullptr), it also contains the level of anisotropy (Rnt = a_nt k)
[in]uref2square of the reference flow velocity
[in]dhhydraulic diameter $ D_H $
[in]rhomass density $ \rho $
[in]mudynamic viscosity $ \nu $

◆ cs_turbulence_bc_set_uninit_inlet_k_eps()

void cs_turbulence_bc_set_uninit_inlet_k_eps ( cs_lnum_t face_id,
double k,
double eps,
double vel_dir[],
double shear_dir[] )

Set inlet boundary condition values for turbulence variables based on given k and epsilon values only if not already initialized.

Parameters
[in]face_idboundary face id
[in]kturbulent kinetic energy
[in]epsturbulent dissipation
[in]vel_dirvelocity direction
[in]shear_dirshear direction, it also contains the level of anisotropy (Rnt = a_nt k)

◆ cs_turbulence_bc_set_uninit_inlet_turb_intensity()

void cs_turbulence_bc_set_uninit_inlet_turb_intensity ( cs_lnum_t face_id,
double uref2,
double t_intensity,
double dh )

Set inlet boundary condition values for turbulence variables based on a diameter $ D_H $, a turbulent intensity $ I $ and the reference velocity $ U_{ref} $ for a circular duct flow with smooth wall, only if not already set.

Apart from assigning values where not already initialized, this function is similar to cs_turbulence_bc_inlet_turb_intensity.

Parameters
[in]face_idboundary face id
[in]uref2square of the reference flow velocity
[in]t_intensityturbulent intensity $ I $
[in]dhhydraulic diameter $ D_H $