Simple.h

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#ifndef Simple_included
#define Simple_included
 
#include <TRUSTTabs_forward.h>
#include <Simpler_Base.h>
 
class Operateur_Grad ;
 
//Description
 
//Ref. International Journal For Numerical Methods In Fluids Vol. 12 P. 81-92
// C. T. Shaw
 
// A = (M/dt + C(Uk) + D)
// Bt and -B denote the gradient and divergence operators respectively
 
// A solution (U,P) is sought in the form:
// U = U* + u'
// P = P* + p'
// where (U*,P*) satisfies the momentum equation and (u',p') is a correction
// applied to satisfy the continuity equation.
 
// (U*,P*) satisfies the momentum equation:
//        A[Uk-1]U*k = -BtP* + Sv + Ss + (M/dt)Uk-1                -> U*k
//
// Subtracting this from the full momentum equation for (U,P) gives an equation on u' and p':
//        A[Uk-1]u' = -Btp'
 
// Keeping only the diagonal part (Da) of A, this becomes:
//        u' = -Da-1Btp'
 
// The full velocity field U satisfies the continuity equation, giving:
//        -Bu' = BU*
// hence (BDa-1Bt)p' = BU*                                         -> p' then u'
 
// At the end of the iteration, the solution is:
//        U = U* + beta_u u'
//        P = P* + beta_p p'
// beta_u and beta_p are relaxation coefficients between 0 and 1.
// In practice, relaxation is applied only to the pressure.
 
// The algorithm can be repeated until convergence ||Uk-Uk-1|| < seuil_convergence_implicite_.
// In practice, only one iteration is needed (seuil_convergence_implicite_ = 1e6).
 
 
class Simple : public Simpler_Base
{
  Declare_instanciable_sans_constructeur(Simple);
 
public :
 
  Simple();
  bool iterer_eqn(Equation_base& equation, const DoubleTab& inconnue, DoubleTab& result, double dt, int numero_iteration, int& ok) override;
  void iterer_NS(Equation_base&, DoubleTab& current, DoubleTab& pression, double, Matrice_Morse&, double, DoubleTrav&,int nb_iter,int& converge, int& ok) override;
  bool iterer_eqs(LIST(OBS_PTR(Equation_base)) eqs, int compteur, int& ok) override;
 
  /* memoization of iterer_eqs: public so that the iterated power of TRUST-NK can share it */
  using list_of_eq_ptr_t = std::vector<intptr_t>;  // a list of pointers to equations.
  std::map<list_of_eq_ptr_t, Matrice_Bloc> mbloc;
 
protected :
 
  DoubleTab Ustar_old;        // U* = alpha_ U*_new + (1-alpha_)*U*_old   in practice alpha = 1
  double alpha_,beta_;  // beta_ : pressure relaxation coefficient  P = P* + beta_*P'  0<beta_<=1
  int with_d_rho_dt_;
 
  Entree& lire(const Motcle&, Entree&) override;
  void calculer_correction_en_vitesse(const DoubleTrav& correction_en_pression, DoubleTrav& gradP, DoubleTrav& correction_en_vitesse,const Matrice_Morse& matrice, const Operateur_Grad& gradient );
 
};
 
void diviser_par_rho_np1_face(Equation_base& eqn, DoubleTab& tab);
 
#endif