Boundary conditions using time table

Compute a time dependent parameter value from a time table defined by the user.

To access a time table defined variable when defining boundary conditions, a callback function of the type of type cs_dof_func_t can be defined, such as the following (for a time table named "inlet_temperature"):

static void
_time_table_t_inlet(cs_lnum_t         n_elts,
                    const cs_lnum_t  *elt_ids,
                    bool              dense_output,
                    void             *input,
                    cs_real_t        *retval)
{
  /* Get current time */
  const cs_real_t time = cs_glob_time_step->t_cur;
 
  /* Compute inlet temperature from time table "inlet_temperature" */
  cs_real_t inlet_temp =
    cs_time_table_compute_time_value("inlet_temperature",
                                     time,
                                     1,      /* 2nd column */
                                     false); /* Don't overwrite last position */
 
  /* Apply values at selected locations */
 
  for (cs_lnum_t i = 0; i < n_elts; i++) {
    const cs_lnum_t  face_id = (elt_ids == nullptr) ? i : elt_ids[i];
    const cs_lnum_t  j = dense_output ? i : face_id;
    retval[j] = inlet_temp;
  }
}

Note that accessing the time table value in the function above is done through the call to cs_time_table_compute_time_value.

The callback function can then be assigned to the zone named "inlet" for variable "scalar1" in the usual way (in cs_user_boundary_conditions_setup):

  cs_equation_param_t  *eqp = cs_equation_param_by_name("scalar_1");
 
  cs_equation_add_bc_by_dof_func(eqp,
                                 CS_BC_DIRICHLET,
                                 "inlet",                // zone name
                                 cs_flag_boundary_face,  // location flag
                                 _time_table_t_inlet,    // callback function
                                 nullptr);                  // input structure