Op_Diff_DG_base.h

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#ifndef Op_Diff_DG_base_included
#define Op_Diff_DG_base_included
 
#include <Op_Diff_Turbulent_base.h>
#include <Operateur_Diff_base.h>
#include <Domaine_DG.h>
#include <TRUST_Ref.h>
#include <SFichier.h>
#include <Champ_Uniforme.h>
 
class Domaine_Cl_DG;
/**
 * @brief This class provides the common infrastructure shared by all DG diffusion operators in TRUST.
 * It handles the association with the DG domain and its boundary conditions, the management of
 * an effective diffusivity field (nu_), and the computation of a stable explicit time step.
 *
 * The stable time step calculation (calculer_dt_stab) follows a diffusive CFL criterion:
 *   dt ~ h^2 / (2 * dim * alpha_max)
 * with special handling for:
 *  - Variable-density flows: rho * h^2 / (2 * dim * nu), with VDF-like and general mesh branches.
 *  - Robin / external-heat-exchange boundary conditions (Echange_externe_impose): the effective
 *    diffusivity is scaled by the Biot number when Bi > 1, making the criterion more conservative.
 *
 * Derived classes are responsible for implementing the actual flux assembly (ajouter()) according
 * to their specific DG formulation.
 */
class Op_Diff_DG_base: public Operateur_Diff_base, public Op_Diff_Turbulent_base
{
  Declare_base(Op_Diff_DG_base);
public:
  void associer(const Domaine_dis_base&, const Domaine_Cl_dis_base&, const Champ_Inc_base&) override;
 
  double calculer_dt_stab() const override;
 
  void associer_diffusivite(const Champ_base& diffu) override
  {
    diffusivite_ = diffu;
    is_var_ = sub_type(Champ_Uniforme, diffu) ? 0 : 1;
    is_aniso_ = (diffu.nb_comp() > 1);
  }
 
  void completer() override;
  const Champ_base& diffusivite() const override { return diffusivite_.valeur(); }
  void mettre_a_jour(double t) override
  {
    Operateur_base::mettre_a_jour(t);
    nu_a_jour_ = 0;
  }
 
  void update_nu() const; //met a jour nu
  inline double nu(int i, int compo) const { return nu_(is_var_ * i, compo); }
 
  DoubleTab& calculer(const DoubleTab&, DoubleTab&) const override;
  int impr(Sortie& os) const override;
 
protected:
  OBS_PTR(Domaine_DG) le_dom_dg_;
  OBS_PTR(Domaine_Cl_DG) la_zcl_dg_;
  mutable SFichier Flux, Flux_moment, Flux_sum; // Fichiers .out
 
  OBS_PTR(Champ_base) diffusivite_;
  mutable int nu_a_jour_ = 0; //si on doit mettre a jour nu
  mutable DoubleTab nu_;
 
  bool is_var_; //if the diffusivity is Uniforme or heterogeneous
  bool is_aniso_; //if the diffusivity is anisotropic
 
};
 
 
#endif /* Op_Diff_DG_base_included */