ENH: Added new Hanning window model

src/randomProcesses/windowModels/Hanning/Hanning.C

@@ -0,0 +1,122 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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))
+{
+    // 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 = (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 (if required)
+    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
+
+// ************************************************************************* //

src/randomProcesses/windowModels/Hanning/Hanning.H

@@ -0,0 +1,125 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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/>.
+
+Class
+    Foam::windowModels::Hanning
+
+Description
+    Hanning window
+
+    The window is described by the function
+    \f[
+        wf = (1 - \alpha) cos(2 \pi t/m);
+    \f]
+
+    Where:
+    \vartable
+        \alpha  | Coefficient with a default value of 0.5
+        t       | time
+        m       | window width
+    \endvartable
+
+    The window can be further manipulated by the controls:
+    - \c symmetric: force the window to be symmetric
+    - \c extended: extend the window by 1 element at start and end to produce
+      non-zero values at the start and end positions.  Note: window is
+      normalised to preserve energy content
+
+SourceFiles
+    Hanning.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Hanning_H
+#define Hanning_H
+
+#include "autoPtr.H"
+#include "runTimeSelectionTables.H"
+#include "windowModel.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace windowModels
+{
+
+/*---------------------------------------------------------------------------*\
+                           Class Hanning Declaration
+\*---------------------------------------------------------------------------*/
+
+class Hanning
+:
+    public windowModel
+{
+
+protected:
+
+    // Protected Member Data
+
+        //- Symmetric switch
+        bool symmetric_;
+
+        //- Extended switch
+        bool extended_;
+
+        //- Window coefficient, default = 0.5
+        scalar alpha_;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("Hanning");
+
+
+    //- Construct from dictionary
+    Hanning(const dictionary& dict, const label nSamples);
+
+    //- Destuctor
+    virtual ~Hanning();
+
+
+    // Public Member Functions
+
+        //- Return the symmetric flag
+        bool symmetric() const;
+
+        //- Return the extended flag
+        bool extended() const;
+
+        //- Return the window coefficient
+        scalar alpha() const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace windowModels
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //