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/*---------------------------------------------------------------------------*\
========= |
\\ / 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/>.
Application
noise
Description
Utility to perform noise analysis of pressure data using the noiseFFT
library.
Control settings are read from the $FOAM_CASE/system/noiseDict dictionary,
or user-specified dictionary using the -dict option. Pressure data is
read using a CSV reader:
Usage
\verbatim
pRef 101325;
N 65536;
nw 100;
f1 25;
fU 10000;
graphFormat raw;
pressureData
{
fileName "pressureData"
nHeaderLine 1; // number of header lines
refColumn 0; // reference column index
componentColumns (1); // component column indices
separator " "; // optional (defaults to ",")
mergeSeparators no; // merge multiple separators
outOfBounds clamp; // optional out-of-bounds handling
interpolationScheme linear; // optional interpolation scheme
}
\endverbatim
where
\table
Property | Description | Required | Default value
pRef | Reference pressure | no | 0
N | Number of samples in sampling window | no | 65536
nw | Number of sampling windows | no | 100
fl | Lower frequency band | no | 25
fU | Upper frequency band | no | 10000
graphFormat | Output graph format | no | raw
\endtable
Current graph outputs include:
- FFT of the pressure data
- narrow-band PFL (pressure-fluctuation level) spectrum
- one-third-octave-band PFL spectrum
- one-third-octave-band pressure spectrum
See also
CSV.H
noiseFFT.H
\*---------------------------------------------------------------------------*/
#include "noiseFFT.H"
#include "argList.H"
#include "Time.H"
#include "writeFiles.H"
#include "CSV.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
using namespace Foam;
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Foam::scalar checkUniformTimeStep(const scalarField& t)
{
// check that a uniform time step has been applied
scalar deltaT = -1.0;
if (t.size() > 1)
{
for (label i = 1; i < t.size(); i++)
{
scalar dT = t[i] - t[i-1];
if (deltaT < 0)
{
deltaT = dT;
}
if (mag(deltaT - dT) > SMALL)
{
FatalErrorInFunction
<< "Unable to process data with a variable time step"
<< exit(FatalError);
}
}
}
else
{
FatalErrorInFunction
<< "Unable to create FFT with a single value"
<< exit(FatalError);
}
return deltaT;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
int main(int argc, char *argv[])
{
argList::noParallel();
#include "addDictOption.H"
#include "setRootCase.H"
#include "createTime.H"
#include "createFields.H"
Info<< "Reading data file" << endl;
Function1Types::CSV<scalar> pData("pressure", dict, "Data");
// time history data
const scalarField t(pData.x());
// pressure data
const scalarField p(pData.y());
if (t.size() < N)
{
FatalErrorInFunction
<< "Block size N = " << N
<< " is larger than number of data = " << t.size()
<< exit(FatalError);
}
Info<< " read " << t.size() << " values" << nl << endl;
Info<< "Creating noise FFT" << endl;
noiseFFT nfft(checkUniformTimeStep(t), p);
nfft -= pRef;
fileName baseFileName(pData.fName().lessExt());
graph Pf(nfft.RMSmeanPf(N, min(nfft.size()/N, nw)));
Info<< " Creating graph for " << Pf.title() << endl;
Pf.write(baseFileName + graph::wordify(Pf.title()), graphFormat);
graph Lf(nfft.Lf(Pf));
Info<< " Creating graph for " << Lf.title() << endl;
Lf.write(baseFileName + graph::wordify(Lf.title()), graphFormat);
graph Ldelta(nfft.Ldelta(Lf, f1, fU));
Info<< " Creating graph for " << Ldelta.title() << endl;
Ldelta.write(baseFileName + graph::wordify(Ldelta.title()), graphFormat);
graph Pdelta(nfft.Pdelta(Pf, f1, fU));
Info<< " Creating graph for " << Pdelta.title() << endl;
Pdelta.write(baseFileName + graph::wordify(Pdelta.title()), graphFormat);
Info<< nl << "End\n" << endl;
return 0;
}
// ************************************************************************* //
|
