Files
openfoam/src/lagrangian/distributionModels/multiNormal/multiNormal.C
Henry Weller 7eaa46a08b massRosinRammler: New Lagrangian size-distribution model
Corrected form of the Rosin-Rammler distribution taking into account the
    varying number of particels per parces for for fixed-mass parcels.  This
    distribution should be used when
    \verbatim
        parcelBasisType mass;
    \endverbatim

    See equation 10 in reference:
    \verbatim
        Yoon, S. S., Hewson, J. C., DesJardin, P. E., Glaze, D. J.,
        Black, A. R., & Skaggs, R. R. (2004).
        Numerical modeling and experimental measurements of a high speed
        solid-cone water spray for use in fire suppression applications.
        International Journal of Multiphase Flow, 30(11), 1369-1388.
    \endverbatim
2016-11-22 15:25:43 +00:00

161 lines
4.1 KiB
C

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
OpenFOAM is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
\*---------------------------------------------------------------------------*/
#include "multiNormal.H"
#include "addToRunTimeSelectionTable.H"
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
namespace Foam
{
namespace distributionModels
{
defineTypeNameAndDebug(multiNormal, 0);
addToRunTimeSelectionTable(distributionModel, multiNormal, dictionary);
}
}
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Foam::distributionModels::multiNormal::multiNormal
(
const dictionary& dict,
cachedRandom& rndGen
)
:
distributionModel(typeName, dict, rndGen),
minValue_(readScalar(distributionModelDict_.lookup("minValue"))),
maxValue_(readScalar(distributionModelDict_.lookup("maxValue"))),
range_(maxValue_ - minValue_),
expectation_(distributionModelDict_.lookup("expectation")),
variance_(distributionModelDict_.lookup("variance")),
strength_(distributionModelDict_.lookup("strength"))
{
check();
scalar sMax = 0;
label n = strength_.size();
for (label i=0; i<n; i++)
{
scalar x = expectation_[i];
scalar s = strength_[i];
for (label j=0; j<n; j++)
{
if (i!=j)
{
scalar x2 = (x - expectation_[j])/variance_[j];
scalar y = exp(-0.5*x2*x2);
s += strength_[j]*y;
}
}
sMax = max(sMax, s);
}
for (label i=0; i<n; i++)
{
strength_[i] /= sMax;
}
}
Foam::distributionModels::multiNormal::multiNormal(const multiNormal& p)
:
distributionModel(p),
minValue_(p.minValue_),
maxValue_(p.maxValue_),
range_(p.range_),
expectation_(p.expectation_),
variance_(p.variance_),
strength_(p.strength_)
{}
// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
Foam::distributionModels::multiNormal::~multiNormal()
{}
// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
Foam::scalar Foam::distributionModels::multiNormal::sample() const
{
scalar y = 0;
scalar x = 0;
label n = expectation_.size();
bool success = false;
while (!success)
{
x = minValue_ + range_*rndGen_.sample01<scalar>();
y = rndGen_.sample01<scalar>();
scalar p = 0.0;
for (label i=0; i<n; i++)
{
scalar nu = expectation_[i];
scalar sigma = variance_[i];
scalar s = strength_[i];
scalar v = (x - nu)/sigma;
p += s*exp(-0.5*v*v);
}
if (y<p)
{
success = true;
}
}
return x;
}
Foam::scalar Foam::distributionModels::multiNormal::minValue() const
{
return minValue_;
}
Foam::scalar Foam::distributionModels::multiNormal::maxValue() const
{
return maxValue_;
}
Foam::scalar Foam::distributionModels::multiNormal::meanValue() const
{
scalar mean = 0.0;
forAll(strength_, i)
{
mean += strength_[i]*expectation_[i];
}
return mean;
}
// ************************************************************************* //