bcs.c

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//##############################################################################
//
// bcs.c
//
//  - Boundary conditions.
//

void bcs( lattice_ptr lattice)
{
  int n;
  int *bc;
  double *ftemp;
  double u_x, u_y, rho;

  bc = &( lattice->bc[0].bc_type);
  ftemp = lattice->pdf[0].ftemp;

  for( n=0; n<lattice->NumNodes; n++)
  {
    if( *bc != 0 && *bc != BC_SOLID_NODE)
    {
      if( *bc & BC_PRESSURE_N_IN ) 
      {
        // North, Inflow

//printf("bcs() -- North, Inflow at n = %d, ( %d, %d)\n", 
//  n, lattice->node[n].i, lattice->node[n].j);
//printf("  Before>> %f %f %f %f [%f] %f %f [%f] [%f]\n",
//    ftemp[0], ftemp[1], ftemp[2],
//    ftemp[3], ftemp[4], ftemp[5],
//    ftemp[6], ftemp[7], ftemp[8]  );

        u_y = -1.
            + ( ftemp[0] + ftemp[1] + ftemp[3]
              + 2.*( ftemp[2] + ftemp[5] + ftemp[6])) 
            / lattice->param.rho_in;
    
        ftemp[4] = ftemp[2] - (2./3.)*lattice->param.rho_in*u_y;
    
        ftemp[7] = ftemp[5] + (1./2.)*( ftemp[1] - ftemp[3])
                            - (1./6.)*lattice->param.rho_in*u_y;
    
        ftemp[8] = ftemp[6] + (1./2.)*( ftemp[3] - ftemp[1])
                            - (1./6.)*lattice->param.rho_in*u_y; 

//printf("  Before>> %f %f %f %f [%f] %f %f [%f] [%f]\n",
//    ftemp[0], ftemp[1], ftemp[2],
//    ftemp[3], ftemp[4], ftemp[5],
//    ftemp[6], ftemp[7], ftemp[8]  );

      } /* if( *bc & BC_PRESSURE_N_IN ) */

      if( *bc & BC_PRESSURE_S_IN ) 
      { 
        printf("bcs() -- ERROR: Support for South, Inflow pressure "
            "boundaries is pending. (Exiting!)");
        exit(1);
      }
      if( *bc & BC_PRESSURE_E_IN )
      { 
        printf("bcs() -- ERROR: Support for East, Inflow pressure "
            "boundaries is pending. (Exiting!)");
        exit(1);
      }
      if( *bc & BC_PRESSURE_W_IN )
      { 
        printf("bcs() -- ERROR: Support for West, Inflow pressure "
            "boundaries is pending. (Exiting!)");
        exit(1);
      }
      if( *bc & BC_PRESSURE_N_OUT)
      { 
        printf("bcs() -- ERROR: Support for North, Outflow pressure "
            "boundaries is pending. (Exiting!)");
        exit(1);
      }

      if( *bc & BC_PRESSURE_S_OUT) 
      { 
        // South, Outflow

//printf("bcs() -- South, Outflow at n = %d, ( %d, %d)\n",
//  n, lattice->node[n].i, lattice->node[n].j);
//printf("  Before>> %f %f [%f] %f %f [%f] [%f] %f %f\n",
//    ftemp[0], ftemp[1], ftemp[2],
//    ftemp[3], ftemp[4], ftemp[5],
//    ftemp[6], ftemp[7], ftemp[8]  );

        u_y = 1.
            - ( ftemp[0] + ftemp[1] + ftemp[3]
              + 2.*( ftemp[4] + ftemp[7] + ftemp[8])) 
            / lattice->param.rho_out;
    
        ftemp[2] = ftemp[4] + (2./3.)*lattice->param.rho_out*u_y;
    
        ftemp[5] = ftemp[7] + (1./2.)*( ftemp[3] - ftemp[1])
                            + (1./6.)*lattice->param.rho_out*u_y;
    
        ftemp[6] = ftemp[8] + (1./2.)*( ftemp[1] - ftemp[3])
                            + (1./6.)*lattice->param.rho_out*u_y; 

//printf("  Before>> %f %f [%f] %f %f [%f] [%f] %f %f\n",
//    ftemp[0], ftemp[1], ftemp[2],
//    ftemp[3], ftemp[4], ftemp[5],
//    ftemp[6], ftemp[7], ftemp[8]  );

      } /* if( *bc & BC_PRESSURE_S_OUT) */

      if( *bc & BC_PRESSURE_E_OUT)
      { 
        printf("bcs() -- ERROR: Support for East, Outflow pressure "
            "boundaries is pending. (Exiting!)");
        exit(1);
      }
      if( *bc & BC_PRESSURE_W_OUT)
      { 
        printf("bcs() -- ERROR: Support for West, Outflow pressure "
            "boundaries is pending. (Exiting!)");
        exit(1);
      }

    } /* if( *bc != 0 && *bc != BC_SOLID_NODE) */

    ftemp+=27;

    bc++;

  } /* for( n=0; n<lattice->NumNodes; n++) */

} /* void bcs( lattice_ptr lattice) */