olb::BoundaryHelpers< T, DESCRIPTOR, direction, orientation > Struct Template Reference

All boundary helper functions are inside this structure. More...

#include <helper.h>

Collaboration diagram for olb::BoundaryHelpers< T, DESCRIPTOR, direction, orientation >:

Static Public Member Functions
template<typename CELL >
static void	computeStress (CELL &cell, T rho, const T u[DESCRIPTOR::d], T pi[util::TensorVal< DESCRIPTOR >::n]) any_platform

Detailed Description

template<typename T, typename DESCRIPTOR, int direction, int orientation>
struct olb::BoundaryHelpers< T, DESCRIPTOR, direction, orientation >

All boundary helper functions are inside this structure.

Definition at line 34 of file helper.h.

Member Function Documentation

computeStress()

template<typename T , typename DESCRIPTOR , int direction, int orientation>

template<typename CELL >

static void olb::BoundaryHelpers< T, DESCRIPTOR, direction, orientation >::computeStress ( CELL & cell, T rho, const T u[DESCRIPTOR::d], T pi[util::TensorVal< DESCRIPTOR >::n] )

inlinestatic

Definition at line 36 of file helper.h.

  {
    const T uSqr = util::normSqr<T,DESCRIPTOR::d>(u);
 
    constexpr auto onWallIndices = util::populationsContributingToVelocity<DESCRIPTOR,direction,0>();
    constexpr auto normalIndices = util::populationsContributingToVelocity<DESCRIPTOR,direction,orientation>();
 
    T fNeq[DESCRIPTOR::q];
    for (unsigned fIndex=0; fIndex<onWallIndices.size(); ++fIndex) {
      int iPop = onWallIndices[fIndex];
      if (iPop == 0) {
        fNeq[0] = T();  // fNeq[0] will not be used anyway
      }
      else {
        fNeq[iPop] =
          cell[iPop] -
          equilibrium<DESCRIPTOR>::secondOrder(iPop, rho, u, uSqr);
      }
    }
    for (unsigned fIndex=0; fIndex<normalIndices.size(); ++fIndex) {
      int iPop = normalIndices[fIndex];
      fNeq[iPop] =
        cell[iPop] -
        equilibrium<DESCRIPTOR>::secondOrder(iPop, rho, u, uSqr);
    }
 
    int iPi = 0;
    for (int iAlpha=0; iAlpha < DESCRIPTOR::d; ++iAlpha) {
      for (int iBeta=iAlpha; iBeta < DESCRIPTOR::d; ++iBeta) {
        pi[iPi] = T();
        for (unsigned fIndex=0; fIndex < onWallIndices.size(); ++fIndex) {
          const int iPop = onWallIndices[fIndex];
          pi[iPi] += descriptors::c<DESCRIPTOR>(iPop,iAlpha)
                   * descriptors::c<DESCRIPTOR>(iPop,iBeta)
                   * fNeq[iPop];
        }
        for (unsigned fIndex=0; fIndex < normalIndices.size(); ++fIndex) {
          const int iPop = normalIndices[fIndex];
          pi[iPi] += T{2}
                   * descriptors::c<DESCRIPTOR>(iPop,iAlpha)
                   * descriptors::c<DESCRIPTOR>(iPop,iBeta)
                   * fNeq[iPop];
        }
        ++iPi;
      }
    }
  }

References olb::equilibrium< DESCRIPTOR >::secondOrder().

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The documentation for this struct was generated from the following file:

• src/boundary/helper.h