Additional right_hand side source terms for turbulence models

Turbulence source terms may be modified using the cs_user_source_terms user-defined function.

Local variables

  /* mesh quantities */
  const cs_lnum_t  n_cells = cs_glob_mesh->n_cells;
  const cs_real_t  *cell_f_vol = cs_glob_mesh_quantities->cell_vol;

Remaining initialization

Get the density array in cpro_rom

const cs_real_t *cpro_rom = CS_F_(rho)->val;

Get the array of the current turbulent variable and its name

  /* Define pointer f to the current turbulent variable field */
  const cs_field_t  *f = cs_field_by_id(f_id);
 
  const cs_var_cal_opt_t  *var_cal_opt
    = cs_field_get_key_struct_const_ptr(f,
                                        cs_field_key_id("var_cal_opt"));

Example

Example of arbitrary additional source term for turbulence models (Source term on the TKE "k" here).

Source term for $\varia:$

$\rho \norm{\vol{\celli}} \frac{d(\varia)}{dt} = ... - \rho \norm{\vol{\celli}} \cdot ff - \rho \frac{ \varia}{\tau}$

with $ ff $ = 3.0 an $\tau$ = 4.0

Body

Note

The turbulence variable names are:

'k' and 'epsilon' for the k-epsilon models
'rij' and 'epsilon' for the Rij-epsilon LRR and S SG
'rij', 'epsilon' and 'alpha' for the EBRSM
'k', 'epsilon', 'phi' and 'f_bar' for the phi-model
'k', 'epsilon', 'phi' and 'alpha' for the Bl-v2-k model
'k' and 'omega' for the k-omega turbulence model
'nu_tilda' for the Spalart Allmaras model

Calculation of the explicit and implicit source terms

  if (f == CS_F_(k)) {
 
    if (var_cal_opt->iwarni >= 1)
      bft_printf(" User source terms for turbulence variable %s\n",
                 cs_field_get_label(f));
 
    const cs_real_t ff  = 3.0;
    const cs_real_t tau = 4.0;
 
    for (cs_lnum_t i = 0; i < n_cells; i++) {
 
      /* explicit source terms */
      st_exp[i] = -cpro_rom[i] * cell_f_vol[i] * ff;
 
      /* implicit source terms */
      st_imp[i] = -cpro_rom[i] * cell_f_vol[i] / tau;
    }
  }