Files
openfoam/src/randomProcesses/windowModels/Hanning/Hanning.C
2016-06-29 20:40:29 +01:00

123 lines
3.2 KiB
C

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2016 OpenCFD Ltd.
\\/ 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 "Hanning.H"
#include "addToRunTimeSelectionTable.H"
#include "mathematicalConstants.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
namespace windowModels
{
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
defineTypeNameAndDebug(Hanning, 0);
addToRunTimeSelectionTable(windowModel, Hanning, dictionary);
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Hanning::Hanning(const dictionary& dict, const label nSamples)
:
windowModel(dict, nSamples),
symmetric_(readBool(dict.lookup("symmetric"))),
extended_(readBool(dict.lookup("extended"))),
alpha_(dict.lookupOrDefault("alpha", 0.5)) // Hamming = 0.54
{
// Extend range if required
label offset = extended_ ? 1 : 0;
scalar m = nSamples - 1 + 2*offset;
scalarField t(nSamples);
forAll(t, i)
{
t[i] = i + offset;
}
scalarField& wf = *this;
wf = alpha_ - (1 - alpha_)*cos(constant::mathematical::twoPi*t/m);
// Reset second half of window if symmetric
if (symmetric_)
{
label midPointI = 0;
if (nSamples % 2 == 0)
{
midPointI = nSamples/2;
}
else
{
midPointI = (nSamples + 1)/2;
}
for (label i = 0; i < midPointI; i++)
{
wf[nSamples - i - 1] = wf[i];
}
}
scalar sumSqr = sum(sqr(wf));
// Normalisation
wf *= sqrt(nSamples/sumSqr);
}
// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
Hanning::~Hanning()
{}
// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
bool Hanning::symmetric() const
{
return symmetric_;
}
bool Hanning::extended() const
{
return extended_;
}
Foam::scalar Hanning::alpha() const
{
return alpha_;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace windowModels
} // End namespace Foam
// ************************************************************************* //