Curle.H

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/*---------------------------------------------------------------------------*\
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-------------------------------------------------------------------------------
    Copyright (C) 2017-2020 OpenCFD Ltd.
-------------------------------------------------------------------------------
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::functionObjects::Curle
 
Group
    grpFieldFunctionObjects
 
Description
    Computes the acoustic pressure based on Curle's analogy.
 
    Curle's analogy is implemented as:
 
    \f[
        p' = \frac{1}{4 \pi}
             \frac{\vec{r}}{| \vec{r} | ^2} \cdot
             \left(
                \frac{\vec{F}}{| \vec{r} |}
              + \frac{1}{c_0}\frac{d(\vec{F})}{d(t)}
             \right)
    \f]
 
    where
    \vartable
        p'          | Curle's acoustic pressure [Pa] or [Pa (m3/kg)]
        c_0         | Reference speed of sound [m/s]
        \vec{r}     | Distance vector to observer locations [m]
        \vec{F}     | Force [N] or [N (m3/kg)]
        t           | time [s]
    \endvartable
 
    Operands:
    \table
      Operand           | Type           | Location
      input             | volScalarField | $FOAM_CASE/<time>/<inpField>
      output file       | -              | -
      output field      | volScalarField | $FOAM_CASE/<time>/<outField>
    \endtable
 
Note
    Only the normal-pressure force is included in the force calculation.
 
Usage
    Minimal example by using \c system/controlDict.functions:
    \verbatim
    Curle1
    {
        type            Curle;
        libs            ("libfieldFunctionObjects.so");
        ...
        patches         (surface1 surface2);
        c0              330;
 
 
        // Input - either points or surface
 
        input           points;
        observerPositions ((0 0 0)(1 0 0));
 
        //input           surface;
        //surface         "inputSurface.obj"
 
 
        // Output - either points or surface
        output          points;
 
        //output          surface;
        //surfaceType     ensight;
    }
    \endverbatim
 
    where the entries mean:
    \table
      Property     | Description                        | Type | Req'd | Dflt
      type         | Type name: Curle                   | word |  yes  | -
      libs         | Library name: fieldFunctionObjects | word |  yes  | -
      p            | Pressure field name                | word |  no   | p
      patches      | Sound generation patch names       | wordList | yes | -
      c0           | Reference speed of sound           | scalar | yes | -
      input        | Input type                         | word | yes   | -
      observerPositions | List of observer positions (x y z) | pointList | no |-
      surface      | Input surface file name            | word | no    | -
      output       | Output type                        | word | yes   | -
      surfaceType  | Output surface type                | word | no    | -
    \endtable
 
    The inherited entries are elaborated in:
     - \link functionObject.H \endlink
     - \link fieldExpression.H \endlink
 
    Usage by the \c postProcess utility is not available.
 
See also
    - Foam::functionObject
    - Foam::functionObjects::fvMeshFunctionObject
    - Foam::functionObjects::writeFile
    - ExtendedCodeGuide::functionObjects::field::Curle
 
SourceFiles
    Curle.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef functionObjects_Curle_H
#define functionObjects_Curle_H
 
#include "fvMeshFunctionObject.H"
#include "writeFile.H"
#include "Enum.H"
#include "MeshedSurface.H"
#include "surfaceWriter.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace functionObjects
{
 
/*---------------------------------------------------------------------------*\
                            Class Curle Declaration
\*---------------------------------------------------------------------------*/
 
class Curle
:
    public fvMeshFunctionObject,
    public writeFile
{
    enum class modeType
    {
        point,
        surface
    };
 
    static const Enum<modeType> modeTypeNames_;
 
 
    // Private Data
 
        //- Name of pressure field; default = p
        word pName_;
 
        //- Patches to integrate forces over
        labelHashSet patchSet_;
 
        //- Observer positions
        List<point> observerPositions_;
 
        //- Reference speed of sound
        scalar c0_;
 
        //- Output files when sampling points
        PtrList<OFstream> rawFilePtrs_;
 
        //- Input surface when sampling a surface
        MeshedSurface<face> inputSurface_;
 
        //- Ouput surface when sampling a surface
        autoPtr<surfaceWriter> surfaceWriterPtr_;
 
 
public:
 
    //- Runtime type information
    TypeName("Curle");
 
 
    // Constructors
 
        //- Construct from Time and dictionary
        Curle
        (
            const word& name,
            const Time& runTime,
            const dictionary& dict
        );
 
        //- No copy construct
        Curle(const Curle&) = delete;
 
        //- No copy assignment
        void operator=(const Curle&) = delete;
 
 
    //- Destructor
    virtual ~Curle() = default;
 
 
    // Member Functions
 
        //- Read the Curle data
        virtual bool read(const dictionary&);
 
        virtual bool execute();
 
        virtual bool write();
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace functionObjects
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //