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noiseFFT.H

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00001 /*---------------------------------------------------------------------------*\
00002   =========                 |
00003   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
00004    \\    /   O peration     |
00005     \\  /    A nd           | Copyright (C) 1991-2010 OpenCFD Ltd.
00006      \\/     M anipulation  |
00007 -------------------------------------------------------------------------------
00008 License
00009     This file is part of OpenFOAM.
00010 
00011     OpenFOAM is free software: you can redistribute it and/or modify it
00012     under the terms of the GNU General Public License as published by
00013     the Free Software Foundation, either version 3 of the License, or
00014     (at your option) any later version.
00015 
00016     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
00017     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00018     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
00019     for more details.
00020 
00021     You should have received a copy of the GNU General Public License
00022     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
00023 
00024 Class
00025     Foam::noiseFFT
00026 
00027 Description
00028     FFT of the pressure field
00029 
00030 SourceFiles
00031     noiseFFT.C
00032 
00033 \*---------------------------------------------------------------------------*/
00034 
00035 #ifndef noiseFFT_H
00036 #define noiseFFT_H
00037 
00038 #include <OpenFOAM/scalarField.H>
00039 #include <OpenFOAM/graph.H>
00040 
00041 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
00042 
00043 namespace Foam
00044 {
00045 
00046 /*---------------------------------------------------------------------------*\
00047                            Class noiseFFT Declaration
00048 \*---------------------------------------------------------------------------*/
00049 
00050 class noiseFFT
00051 :
00052     public scalarField
00053 {
00054     // Private data
00055 
00056         //- Time spacing of the raw data
00057         scalar deltat_;
00058 
00059 
00060 public:
00061 
00062     //- Reference pressure
00063     static scalar p0;
00064 
00065 
00066     // Constructors
00067 
00068         //- Construct from pressure field
00069         noiseFFT
00070         (
00071             const scalar deltat,
00072             const scalarField& pressure
00073         );
00074 
00075         //- Construct from Istream
00076         noiseFFT(Istream&);
00077 
00078         //- Construct from pressure field file name
00079         noiseFFT(const fileName& pFileName, const label skip = 0);
00080 
00081 
00082     // Member Functions
00083 
00084         //- Return the graph of p(t)
00085         graph pt() const;
00086 
00087         //- Return the nth window
00088         tmp<scalarField> window(const label N, const label n) const;
00089 
00090         //- Return the Hanning window function
00091         tmp<scalarField> Hanning(const label N) const;
00092 
00093         //- Return the fft of the given pressure data
00094         tmp<scalarField> Pf(const tmp<scalarField>& pn) const;
00095 
00096         //- Return the multi-window mean fft of the complete pressure data
00097         graph meanPf(const label N, const label nw) const;
00098 
00099         //- Return the multi-window RMS mean fft of the complete pressure data
00100         graph RMSmeanPf(const label N, const label nw) const;
00101 
00102         //- Return the narrow-band PFL (pressure-fluctuation level) spectrum
00103         graph Lf(const graph& gPf) const;
00104 
00105         //- Return the one-third-octave-band PFL spectrum
00106         //  starting at octave with mean frequency f1
00107         graph Ldelta(const graph& gLf, const scalar f1, const scalar fU) const;
00108 
00109         //- Return the one-third-octave-band pressure spectrum
00110         //  starting at octave with mean frequency f1
00111         graph Pdelta(const graph& gLf, const scalar f1, const scalar fU) const;
00112 
00113         //- Return the total PFL as the sum of Lf over all frequencies
00114         scalar Lsum(const graph& gLf) const;
00115 
00116         //- Convert the db into Pa
00117         scalar dbToPa(const scalar db) const;
00118 
00119         //- Convert the db-field into Pa
00120         tmp<scalarField> dbToPa(const tmp<scalarField>& db) const;
00121 };
00122 
00123 
00124 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
00125 
00126 } // End namespace Foam
00127 
00128 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
00129 
00130 #endif
00131 
00132 // ************************ vim: set sw=4 sts=4 et: ************************ //
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