meanVelocityForce.H

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/*---------------------------------------------------------------------------*\
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    Copyright (C) 2011-2017 OpenFOAM Foundation
    Copyright (C) 2020 OpenCFD Ltd.
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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.
 
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    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::fv::meanVelocityForce
 
Group
    grpFvOptionsSources
 
Description
    Applies the force within a specified region to maintain
    the specified mean velocity for incompressible flows.
 
    Sources applied to:
    \verbatim
      U         | Velocity                                   [m/s]
    \endverbatim
 
    Required fields:
    \verbatim
      U         | Velocity                                   [m/s]
    \endverbatim
 
Usage
    Minimal example by using \c constant/fvOptions:
    \verbatim
    meanVelocityForce1
    {
        // Mandatory entries (unmodifiable)
        type                 meanVelocityForce;
 
        // Mandatory entries (unmodifiable)
        Ubar             (1 0 0);
        fields           (<fieldName>);
 
        // Optional entries (unmodifiable)
        relaxation       1.0;
 
        // Conditional mandatory entries (unmodifiable)
 
            // when <timePath>/uniform/<name>Properties file exists
            gradient    <vectorField>; // reading from the aforementioned file
 
        // Mandatory/Optional (inherited) entries
        ...
    }
    \endverbatim
 
    where the entries mean:
    \table
      Property  | Description                       | Type   | Reqd  | Dflt
      type      | Type name: meanVelocityForce      | word   | yes   | -
      Ubar      | Desired mean velocity             | vector | yes   | -
      fields    | Name of operand velocity field    | word   | yes   | -
      relaxation | Relaxation factor                | scalar | no    | 1
      gradient  | Initial pressure gradient field   | vectorField | cndtnl | -
    \endtable
 
    The inherited entries are elaborated in:
     - \link fvOption.H \endlink
     - \link cellSetOption.H \endlink
 
Note
  - Currently only handles kinematic pressure (incompressible solvers).
 
SourceFiles
    meanVelocityForce.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef meanVelocityForce_H
#define meanVelocityForce_H
 
#include "autoPtr.H"
#include "fvMesh.H"
#include "volFields.H"
#include "cellSetOption.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace fv
{
 
/*---------------------------------------------------------------------------*\
               Class meanVelocityForce Declaration
\*---------------------------------------------------------------------------*/
 
class meanVelocityForce
:
    public fv::cellSetOption
{
protected:
 
    // Protected Data
 
        //- Desired mean velocity
        vector Ubar_;
 
        //- Pressure gradient before correction
        scalar gradP0_;
 
        //- Change in pressure gradient
        scalar dGradP_;
 
        //- Flow direction
        vector flowDir_;
 
        //- Relaxation factor
        scalar relaxation_;
 
        //- Matrix 1/A coefficients field pointer
        autoPtr<volScalarField> rAPtr_;
 
 
    // Protected Member Functions
 
        //- Calculate and return the magnitude of the mean velocity
        //- averaged over the selected cellSet
        virtual scalar magUbarAve(const volVectorField& U) const;
 
        //- Write the pressure gradient to file (for restarts etc)
        void writeProps(const scalar gradP) const;
 
        //- Correct driving force for a constant mass flow rate
        void update(fvMatrix<vector>& eqn);
 
 
public:
 
    //- Runtime type information
    TypeName("meanVelocityForce");
 
 
    // Constructors
 
        //- Construct from explicit source name and mesh
        meanVelocityForce
        (
            const word& sourceName,
            const word& modelType,
            const dictionary& dict,
            const fvMesh& mesh
        );
 
        //- No copy construct
        meanVelocityForce(const meanVelocityForce&) = delete;
 
        //- No copy assignment
        void operator=(const meanVelocityForce&) = delete;
 
 
    //- Destructor
    virtual ~meanVelocityForce() = default;
 
 
    // Member Functions
 
        // Evaluation
 
            //- Correct the pressure gradient
            virtual void correct(volVectorField& U);
 
            //- Add explicit contribution to momentum equation
            virtual void addSup
            (
                fvMatrix<vector>& eqn,
                const label fieldi
            );
 
            //- Add explicit contribution to compressible momentum equation
            virtual void addSup
            (
                const volScalarField& rho,
                fvMatrix<vector>& eqn,
                const label fieldi
            );
 
            //- Set 1/A coefficient
            virtual void constrain
            (
                fvMatrix<vector>& eqn,
                const label fieldi
            );
 
 
        // IO
 
            //- Read source dictionary
            virtual bool read(const dictionary& dict);
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace fv
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //