ShallowWater2DComputeCFL.c File Reference

Contains the function to compute maximum CFL over the domain for the 2D shallow water equations physical model. More...

#include <stdlib.h>
#include <basic.h>
#include <math.h>
#include <arrayfunctions.h>
#include <mathfunctions.h>
#include <physicalmodels/shallowwater2d.h>
#include <hypar.h>

Go to the source code of this file.

Functions
double	ShallowWater2DComputeCFL (void *s, void *m, double dt, double t)

Detailed Description

Contains the function to compute maximum CFL over the domain for the 2D shallow water equations physical model.

Author

Debojyoti Ghosh

Definition in file ShallowWater2DComputeCFL.c.

Function Documentation

ShallowWater2DComputeCFL()

double ShallowWater2DComputeCFL	(	void *	s,
		void *	m,
		double	dt,
		double	t
	)

Computes the maximum CFL number over the domain. Note that the CFL is computed over the local domain on this processor only.

Parameters

s	Solver object of type HyPar
m	MPI object of type MPIVariables
dt	Time step size for which to compute the CFL
t	Time

Definition at line 17 of file ShallowWater2DComputeCFL.c.

{
  HyPar           *solver = (HyPar*)   s;
  ShallowWater2D  *param  = (ShallowWater2D*) solver->physics;

  int *dim    = solver->dim_local;
  int ghosts  = solver->ghosts;
  int ndims   = solver->ndims;
  int index[ndims];
  double *u   = solver->u;

  double max_cfl = 0;
  int done = 0; _ArraySetValue_(index,ndims,0);
  while (!done) {
    int p; _ArrayIndex1D_(ndims,dim,index,ghosts,p);
    double h, uvel, vvel, c, dxinv, dyinv, local_cfl[_MODEL_NDIMS_];
    _ShallowWater2DGetFlowVar_((u+_MODEL_NVARS_*p),h,uvel,vvel);

    _GetCoordinate_(_XDIR_,index[_XDIR_],dim,ghosts,solver->dxinv,dxinv); /* 1/dx */
    _GetCoordinate_(_YDIR_,index[_YDIR_],dim,ghosts,solver->dxinv,dyinv); /* 1/dy */
    c = sqrt(param->g*h); /* speed of gravity waves */
    local_cfl[_XDIR_]=(absolute(uvel)+c)*dt*dxinv;/* local cfl for this grid point (x) */
    local_cfl[_YDIR_]=(absolute(vvel)+c)*dt*dyinv;/* local cfl for this grid point (y) */
    if (local_cfl[_XDIR_] > max_cfl) max_cfl = local_cfl[_XDIR_];
    if (local_cfl[_YDIR_] > max_cfl) max_cfl = local_cfl[_YDIR_];

    _ArrayIncrementIndex_(ndims,dim,index,done);
  }

  return(max_cfl);
}