Limiter.cpp File Reference

Limiter functions for the conservative variables. More...

#include "Carmen.h"

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Functions
real	Limiter (const real r)
	Returns the valur of slope limiter from a real value x. More...
Vector	Limiter (const Vector u, const Vector v)
	Returns the value of the slope limiter between the slopes u and v. More...

Detailed Description

Limiter functions for the conservative variables.

Function Documentation

real Limiter

(

const real

x

)

Returns the valur of slope limiter from a real value x.

Parameters

x

...

Returns

double

{
  real Result = 0.;

  switch (LimiterNo)
  {
    case 1: // Min-Mod
        Result = Max(0., Min(1.,r));
        break;

    case 2: // Van Albada
        Result = (r<=0.)? 0.: (r*r+r)/(r*r+1.);
        break;

    case 3: // Van Leer
        Result = (r<=0.) ? 0.: (r+Abs(r))/(1.+Abs(r));
        break;

    case 4: // Superbee
        Result = (r<=0.) ? 0.: Max(0.,Max(Min(2.*r,1.),Min(r,2.)));
        break;
    case 5: // Monotonized Central
        Result = max(0.0,min(min(2*r,0.5*(1+r)),2.0));
        break;

  };

        return Result;
}

Vector Limiter	(	const Vector	u,
		const Vector	v
	)

Returns the value of the slope limiter between the slopes u and v.

Parameters

u	Vector
v	Vector

Returns

Vector

{
        // Min Mod limiter

        int LimiterNo = 3;

        Vector Result(u.dimension());
        int i;
        real x, y;  // slopes

    for (i=1; i<=u.dimension(); i++)
        {
            x = u.value(i);
            y = v.value(i);

            switch(LimiterNo)
            {
                // MIN-MOD
                case 1:
                    if (x == y)
                        Result.setValue(i, 0.);
                    else
                        Result.setValue(i,Min(1., fabs(x)/fabs(x-y)));
                    break;

        // VAN LEER
                case 3:
                default:
                    if ((fabs(x) + fabs(y)) == 0.)
                        Result.setValue(i, 0.);
                    else
                        Result.setValue(i,fabs(x)/(fabs(x)+fabs(y)));
                    break;
            };
        }

        return Result;
}

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