OpenFOAM-5.x/src/randomProcesses/noise/noiseFFT.C

454 lines
8.6 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 "noiseFFT.H"
#include "IFstream.H"
#include "DynamicList.H"
#include "fft.H"
#include "SubField.H"
#include "mathematicalConstants.H"
// * * * * * * * * * * * * * * Static Member Data * * * * * * * * * * * * * //
Foam::scalar Foam::noiseFFT::p0 = 2e-5;
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Foam::noiseFFT::noiseFFT
(
const scalar deltat,
const scalarField& pressure
)
:
scalarField(pressure),
deltat_(deltat)
{}
Foam::noiseFFT::noiseFFT(const fileName& pFileName, const label skip)
:
scalarField(),
deltat_(0.0)
{
// Construct pressure data file
IFstream pFile(pFileName);
// Check pFile stream is OK
if (!pFile.good())
{
FatalErrorInFunction
<< "Cannot read file " << pFileName
<< exit(FatalError);
}
if (skip)
{
scalar dummyt, dummyp;
for (label i=0; i<skip; i++)
{
pFile >> dummyt;
if (!pFile.good() || pFile.eof())
{
FatalErrorInFunction
<< "Number of points in file " << pFileName
<< " is less than the number to be skipped = " << skip
<< exit(FatalError);
}
pFile >> dummyp;
}
}
scalar t = 0, T = 0;
DynamicList<scalar> pData(100000);
label i = 0;
while (!(pFile >> t).eof())
{
T = t;
pFile >> pData(i++);
}
deltat_ = T/pData.size();
this->transfer(pData);
}
// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
Foam::graph Foam::noiseFFT::pt() const
{
scalarField t(size());
forAll(t, i)
{
t[i] = i*deltat_;
}
return graph
(
"p(t)",
"t [s]",
"p(t) [Pa]",
t,
*this
);
}
Foam::tmp<Foam::scalarField> Foam::noiseFFT::window
(
const label N,
const label ni
) const
{
label windowOffset = N;
if ((N + ni*windowOffset) > size())
{
FatalErrorInFunction
<< "Requested window is outside set of data" << endl
<< "number of data = " << size() << endl
<< "size of window = " << N << endl
<< "window = " << ni
<< exit(FatalError);
}
tmp<scalarField> tpw(new scalarField(N));
scalarField& pw = tpw.ref();
label offset = ni*windowOffset;
forAll(pw, i)
{
pw[i] = operator[](i + offset);
}
return tpw;
}
Foam::tmp<Foam::scalarField> Foam::noiseFFT::Hanning(const label N) const
{
scalarField t(N);
forAll(t, i)
{
t[i] = i*deltat_;
}
scalar T = N*deltat_;
return 2*(0.5 - 0.5*cos(constant::mathematical::twoPi*t/T));
}
Foam::tmp<Foam::scalarField> Foam::noiseFFT::Pf
(
const tmp<scalarField>& tpn
) const
{
tmp<scalarField> tPn2
(
mag
(
fft::reverseTransform
(
ReComplexField(tpn),
labelList(1, tpn().size())
)
)
);
tpn.clear();
tmp<scalarField> tPn
(
new scalarField
(
scalarField::subField(tPn2(), tPn2().size()/2)
)
);
scalarField& Pn = tPn.ref();
Pn *= 2.0/sqrt(scalar(tPn2().size()));
Pn[0] /= 2.0;
return tPn;
}
Foam::graph Foam::noiseFFT::meanPf
(
const label N,
const label nw
) const
{
if (N > size())
{
FatalErrorInFunction
<< "Requested window is outside set of data" << nl
<< "number of data = " << size() << nl
<< "size of window = " << N << nl
<< "window = " << nw
<< exit(FatalError);
}
scalarField MeanPf(N/2, 0.0);
scalarField Hwf(Hanning(N));
for (label wi=0; wi<nw; ++wi)
{
MeanPf += Pf(Hwf*window(N, wi));
}
MeanPf /= nw;
scalarField f(MeanPf.size());
scalar deltaf = 1.0/(N*deltat_);
forAll(f, i)
{
f[i] = i*deltaf;
}
return graph
(
"P(f)",
"f [Hz]",
"P(f) [Pa]",
f,
MeanPf
);
}
Foam::graph Foam::noiseFFT::RMSmeanPf
(
const label N,
const label nw
) const
{
if (N > size())
{
FatalErrorInFunction
<< "Requested window is outside set of data" << endl
<< "number of data = " << size() << endl
<< "size of window = " << N << endl
<< "window = " << nw
<< exit(FatalError);
}
scalarField RMSMeanPf(N/2, 0.0);
scalarField Hwf(Hanning(N));
for (label wi=0; wi<nw; ++wi)
{
RMSMeanPf += sqr(Pf(Hwf*window(N, wi)));
}
RMSMeanPf = sqrt(RMSMeanPf/nw);
scalarField f(RMSMeanPf.size());
scalar deltaf = 1.0/(N*deltat_);
forAll(f, i)
{
f[i] = i*deltaf;
}
return graph
(
"P(f)",
"f [Hz]",
"P(f) [Pa]",
f,
RMSMeanPf
);
}
Foam::graph Foam::noiseFFT::Lf(const graph& gPf) const
{
return graph
(
"L(f)",
"f [Hz]",
"L(f) [dB]",
gPf.x(),
20*log10(gPf.y()/p0)
);
}
Foam::graph Foam::noiseFFT::Ldelta
(
const graph& gLf,
const scalar f1,
const scalar fU
) const
{
const scalarField& f = gLf.x();
const scalarField& Lf = gLf.y();
scalarField ldelta(Lf.size(), 0.0);
scalarField fm(ldelta.size());
scalar fratio = cbrt(2.0);
scalar deltaf = 1.0/(2*Lf.size()*deltat_);
scalar fl = f1/sqrt(fratio);
scalar fu = fratio*fl;
label istart = label(fl/deltaf);
label j = 0;
for (label i = istart; i<Lf.size(); i++)
{
scalar fmi = sqrt(fu*fl);
if (fmi > fU + 1) break;
if (f[i] >= fu)
{
fm[j] = fmi;
ldelta[j] = 10*log10(ldelta[j]);
j++;
fl = fu;
fu *= fratio;
}
ldelta[j] += pow(10, Lf[i]/10.0);
}
fm.setSize(j);
ldelta.setSize(j);
return graph
(
"Ldelta",
"fm [Hz]",
"Ldelta [dB]",
fm,
ldelta
);
}
Foam::graph Foam::noiseFFT::Pdelta
(
const graph& gPf,
const scalar f1,
const scalar fU
) const
{
const scalarField& f = gPf.x();
const scalarField& Pf = gPf.y();
scalarField pdelta(Pf.size(), 0.0);
scalarField fm(pdelta.size());
scalar fratio = cbrt(2.0);
scalar deltaf = 1.0/(2*Pf.size()*deltat_);
scalar fl = f1/sqrt(fratio);
scalar fu = fratio*fl;
label istart = label(fl/deltaf + 1.0 - SMALL);
label j = 0;
for (label i = istart; i<Pf.size(); i++)
{
scalar fmi = sqrt(fu*fl);
if (fmi > fU + 1) break;
if (f[i] >= fu)
{
fm[j] = fmi;
pdelta[j] = sqrt((2.0/3.0)*pdelta[j]);
j++;
fl = fu;
fu *= fratio;
}
pdelta[j] += sqr(Pf[i]);
}
fm.setSize(j);
pdelta.setSize(j);
return graph
(
"Pdelta",
"fm [Hz]",
"Pdelta [dB]",
fm,
pdelta
);
}
Foam::scalar Foam::noiseFFT::Lsum(const graph& gLf) const
{
const scalarField& Lf = gLf.y();
scalar lsum = 0.0;
forAll(Lf, i)
{
lsum += pow(10, Lf[i]/10.0);
}
lsum = 10*log10(lsum);
return lsum;
}
Foam::scalar Foam::noiseFFT::dbToPa(const scalar db) const
{
return p0*pow(10.0, db/20.0);
}
Foam::tmp<Foam::scalarField> Foam::noiseFFT::dbToPa
(
const tmp<scalarField>& db
) const
{
return p0*pow(10.0, db/20.0);
}
// ************************************************************************* //