Field_uniform_keps_from_ud.cpp

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#include <Field_uniform_keps_from_ud.h>
#include <Param.h>
 
// XD field_uniform_keps_from_ud field_base field_uniform_keps_from_ud BRACE field which allows to impose on a domain K
// XD_CONT and EPS values derived from U velocity and D hydraulic diameter
Implemente_instanciable(Field_uniform_keps_from_ud,"Field_uniform_keps_from_ud",Champ_Uniforme);
 
 
 
/*! @brief Imprime le champ sur flot de sortie.
 *
 * Imprime la taille du champ et la valeur (constante) sur le domaine
 *
 * @param (Sortie& os) un flot de sortie
 * @return (Sortie&) le flot de sortie modifie
 */
Sortie& Field_uniform_keps_from_ud::printOn(Sortie& os) const
{
  const DoubleTab& tab=valeurs();
  os << tab.size() << " ";
  for(int i=0; i<tab.size(); i++)
    os << tab(0,i);
  return os;
}
 
 
/*! @brief Lit le champ a partir d'un flot d'entree.
 *
 * Format:
 *       Field_uniform_keps_from_ud nb_compo u_value d_value
 *       we expect that nb_compo=2 (one for u and one for d)
 *
 * @param (Entree& is) un flot d'entree
 * @return (Entree& is) le flot d'entree modifie
 */
Entree& Field_uniform_keps_from_ud::readOn(Entree& is)
{
  DoubleTab& tab=valeurs();
  double u=0,d=0;
  Param param(que_suis_je());
  param.ajouter("U", &u, Param::REQUIRED);  // XD_ADD_P floattant
  // XD_CONT value of velocity specified in boundary condition.
  param.ajouter("D", &d, Param::REQUIRED);  // XD_ADD_P floattant
  // XD_CONT value of hydraulic diameter specified in boundary condition
  param.lire_avec_accolades(is);
 
  int keps_size=2;// k and eps
  tab.resize(1,keps_size);
  fixer_nb_comp(keps_size);
 
  //Now compute associated K and Eps by appling formula given by :
  //http://en.wikipedia.org/wiki/Turbulence_kinetic_energy
  //http://www.cfd-online.com/Wiki/Turbulence_length_
  //http://support.esi-cfd.com/esi-users/turb_parameters/
 
  //Hypothesis:
  //Cmu=0.09 : k-eps parameter
  //l=0.038 Dh where Dh is the hydraulic diameter
  //Note that Cmu^(3/4)=0.1643
  double I=0.05;  //: initial turbulence intensity
 
  //in 3D we have
  //k = 3/2*(u*I)^2
  //in 2D we have
  //k = (u*I)^2
  //with u = initial velocity magnitude
  //eps = Cmu^(3/4) * k^(3/2) * l^(-1)
  //where l is the turbulence length scale which can be expressed as 0.038 Dh
  //Dh is the hydraulic diameter
  double l=0.038*d;
  double k = ( dimension == 2 ? 1 : 3./2. )*(u*I)*(u*I);
 
  double eps = 0.1643*pow(k,1.5)/l;
  tab(0,0)=k;
  tab(0,1)=eps;
 
  return is;
}