BCSubsonicOutflow.c File Reference

Subsonic outflow boundary conditions (specific to Euler/Navier-Stokes systems) More...

#include <stdlib.h>
#include <basic.h>
#include <arrayfunctions.h>
#include <boundaryconditions.h>
#include <physicalmodels/euler2d.h>
#include <physicalmodels/navierstokes3d.h>

Go to the source code of this file.

Functions
int	BCSubsonicOutflowU (void *b, void *m, int ndims, int nvars, int *size, int ghosts, double *phi, double waqt)

Detailed Description

Subsonic outflow boundary conditions (specific to Euler/Navier-Stokes systems)

Author

Debojyoti Ghosh

Definition in file BCSubsonicOutflow.c.

Function Documentation

BCSubsonicOutflowU()

int BCSubsonicOutflowU	(	void *	b,
		void *	m,
		int	ndims,
		int	nvars,
		int *	size,
		int	ghosts,
		double *	phi,
		double	waqt
	)

Applies the subsonic outflow boundary condition: The pressure at the physical boundary ghost points is specified, while the density and velocity are extrapolated from the interior. This boundary condition is specific to two and three dimensional Euler/ Navier-Stokes systems (Euler2D, NavierStokes2D, NavierStokes3D).

Parameters

b	Boundary object of type DomainBoundary
m	MPI object of type MPIVariables
ndims	Number of spatial dimensions
nvars	Number of variables/DoFs per grid point
size	Integer array with the number of grid points in each spatial dimension
ghosts	Number of ghost points
phi	The solution array on which to apply the boundary condition
waqt	Current solution time

Definition at line 19 of file BCSubsonicOutflow.c.

{
  DomainBoundary *boundary = (DomainBoundary*) b;

  int dim   = boundary->dim;
  int face  = boundary->face;

  if (ndims == 2) {

    /* create a fake physics object */
    Euler2D physics; 
    double gamma;
    gamma = physics.gamma = boundary->gamma;
    double inv_gamma_m1 = 1.0/(gamma-1.0);

    if (boundary->on_this_proc) {
      int bounds[ndims], indexb[ndims], indexi[ndims];
      _ArraySubtract1D_(bounds,boundary->ie,boundary->is,ndims);
      _ArraySetValue_(indexb,ndims,0);
      int done = 0;
      while (!done) {
        int p1, p2;
        _ArrayCopy1D_(indexb,indexi,ndims);
        _ArrayAdd1D_(indexi,indexi,boundary->is,ndims);
        if      (face ==  1) indexi[dim] = ghosts-1-indexb[dim];
        else if (face == -1) indexi[dim] = size[dim]-indexb[dim]-1;
        else return(1);
        _ArrayIndex1DWO_(ndims,size,indexb,boundary->is,ghosts,p1);
        _ArrayIndex1D_(ndims,size,indexi,ghosts,p2);
        
        /* flow variables in the interior */
        double rho, uvel, vvel, energy, pressure;
        double rho_gpt, uvel_gpt, vvel_gpt, energy_gpt, pressure_gpt;
        _Euler2DGetFlowVar_((phi+nvars*p2),rho,uvel,vvel,energy,pressure,(&physics));
        /* set the ghost point values */
        rho_gpt = rho;
        pressure_gpt = pressure; /* useless statement to avoid compiler warning */
        pressure_gpt = boundary->FlowPressure;
        uvel_gpt = uvel;
        vvel_gpt = vvel;
        energy_gpt = inv_gamma_m1*pressure_gpt
                    + 0.5 * rho_gpt * (uvel_gpt*uvel_gpt + vvel_gpt*vvel_gpt);

        phi[nvars*p1+0] = rho_gpt;
        phi[nvars*p1+1] = rho_gpt * uvel_gpt;
        phi[nvars*p1+2] = rho_gpt * vvel_gpt;
        phi[nvars*p1+3] = energy_gpt;

        _ArrayIncrementIndex_(ndims,bounds,indexb,done);
      }
    }

  } else if (ndims == 3) {

    /* create a fake physics object */
    double gamma;
    gamma = boundary->gamma;
    double inv_gamma_m1 = 1.0/(gamma-1.0);

    if (boundary->on_this_proc) {
      int bounds[ndims], indexb[ndims], indexi[ndims];
      _ArraySubtract1D_(bounds,boundary->ie,boundary->is,ndims);
      _ArraySetValue_(indexb,ndims,0);
      int done = 0;
      while (!done) {
        int p1, p2;
        _ArrayCopy1D_(indexb,indexi,ndims);
        _ArrayAdd1D_(indexi,indexi,boundary->is,ndims);
        if      (face ==  1) indexi[dim] = ghosts-1-indexb[dim];
        else if (face == -1) indexi[dim] = size[dim]-indexb[dim]-1;
        else return(1);
        _ArrayIndex1DWO_(ndims,size,indexb,boundary->is,ghosts,p1);
        _ArrayIndex1D_(ndims,size,indexi,ghosts,p2);
        
        /* flow variables in the interior */
        double rho, uvel, vvel, wvel, energy, pressure;
        double rho_gpt, uvel_gpt, vvel_gpt, wvel_gpt, energy_gpt, pressure_gpt;
        _NavierStokes3DGetFlowVar_((phi+nvars*p2),_NavierStokes3D_stride_,rho,uvel,vvel,wvel,energy,pressure,gamma);
        /* set the ghost point values */
        rho_gpt = rho;
        pressure_gpt = pressure; /* useless statement to avoid compiler warning */
        pressure_gpt = boundary->FlowPressure;
        uvel_gpt = uvel;
        vvel_gpt = vvel;
        wvel_gpt = wvel;
        energy_gpt = inv_gamma_m1*pressure_gpt
                    + 0.5 * rho_gpt 
                    * (uvel_gpt*uvel_gpt + vvel_gpt*vvel_gpt + wvel_gpt*wvel_gpt);

        phi[nvars*p1+0] = rho_gpt;
        phi[nvars*p1+1] = rho_gpt * uvel_gpt;
        phi[nvars*p1+2] = rho_gpt * vvel_gpt;
        phi[nvars*p1+3] = rho_gpt * wvel_gpt;
        phi[nvars*p1+4] = energy_gpt;

        _ArrayIncrementIndex_(ndims,bounds,indexb,done);
      }
    }

  }
  return(0);
}