For velocity components equation (Navier-Stokes)

Additional right-hand side source terms for velocity components equation (Navier-Stokes)

Local variables and initialization

  /* field structure */
  const cs_field_t  *f = cs_field_by_id(f_id);
 
  /* 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;
 
  /* density */
  const cs_real_t  *cpro_rom = CS_F_(rho)->val;

Example

Example of arbitrary source term for component :

appearing in the equation under the form:

In the following example:

with:

• CKP = 1.0 (in ) (return term on velocity)
  
• MMT = 100.0 (in ) (momentum production by volume and time unit)

which yields:

• st_imp[i][0][0] = volume[i] * A = - volume[i]*(rho*CKP)
  
• st_exp[i][0] = volume[i] * B = volume[i]*(XMMT)

Body

  if (f == CS_F_(vel)) { /* velocity */
 
    /* cast to 3D vectors for readability */
    cs_real_3_t    *_st_exp = (cs_real_3_t *)st_exp;
    cs_real_33_t   *_st_imp = (cs_real_33_t *)st_imp;
 
    /* Density */
 
    const cs_real_t ckp = 10.0;
    const cs_real_t xmmt = 100.0;
 
    for (cs_lnum_t i = 0; i < n_cells; i++) {
      _st_imp[i][0][0] = - cell_f_vol[i] * cpro_rom[i] * ckp;
      _st_exp[i][0]    =   cell_f_vol[i] * cpro_rom[i] * xmmt;
    }
 
  }

Example of a boussinesq momentum source term

Example to add Boussinesq source to the z component of :

Body

  if (f == CS_F_(vel) && CS_F_(t) != NULL) { /* velocity and temperature */
 
    /* expansion coefficient and reference density */
 
    const cs_real_t beta = 1.;
    const cs_real_t ro0  = cs_glob_fluid_properties->ro0;
    const cs_real_t t0  = cs_glob_fluid_properties->t0;
 
    /* get temperature */
 
    const cs_real_t *cvar_temperature = CS_F_(t)->val;
 
    cs_real_3_t  *_st_exp = (cs_real_3_t *)st_exp;
 
    for (cs_lnum_t i = 0; i < n_cells; i++) {
      _st_exp[c_id] = cell_f_vol[c_id] * rh0 * beta * (cvar_temperature[i]-t0);
    }
 
  }