velocityDampingConstraint.H

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    Copyright (C) 2015 OpenFOAM Foundation
    Copyright (C) 2015-2020 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.
 
    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::fv::velocityDampingConstraint
 
Group
    grpFvOptionsConstraints
 
Description
    Constrain given velocity fields to dampen velocity
    fluctuations exceeding a given value within a specified region.
 
    This constraint is primarily used to dampen velocity fluctuations in
    the start-up phase of simulations. When the local velocity magnitude
    exceeds the user-supplied maximum value a sink term is activated in
    the affected region to lower the velocity to the limiting value.
 
    Constraints 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
    velocityDampingConstraint1
    {
        // Mandatory entries (unmodifiable)
        type            velocityDampingConstraint;
 
        // Mandatory entries (runtime modifiable)
        UMax            200;
 
        // Optional entries (runtime modifiable)
        UNames          (<Uname1> <Uname2> ... <UnameN>);
 
        // Conditional optional entries (runtime modifiable)
 
            // when UNames entry is not present
            U               U;
 
        // Mandatory/Optional (inherited) entries
        ...
    }
    \endverbatim
 
    where the entries mean:
    \table
      Property  | Description                           | Type   | Reqd  | Dflt
      type      | Type name: velocityDampingConstraint  | word   | yes   | -
      UMax      | Maximum velocity magnitude            | scalar | yes   | -
      UNames    | Names of operand velocity fields      | wordList | no  | -
      U         | Name of operand velocity field        | word   | cndtnl | U
    \endtable
 
    The inherited entries are elaborated in:
     - \link fvOption.H \endlink
     - \link cellSetOption.H \endlink
 
Note
  - When active, this constraint manipulates the system of equations.
    Users should ensure that it is not active when the case is converged
    (steady-state) or during the period of interest (transient) to ensure
    that its presence does not pollute the results.
 
See also
  - Foam::fv::limitVelocity
 
SourceFiles
    velocityDampingConstraint.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef velocityDampingConstraint_H
#define velocityDampingConstraint_H
 
#include "cellSetOption.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace fv
{
 
/*---------------------------------------------------------------------------*\
                  Class velocityDampingConstraint Declaration
\*---------------------------------------------------------------------------*/
 
class velocityDampingConstraint
:
    public fv::cellSetOption
{
protected:
 
    // Protected Data
 
        //- Maximum velocity magnitude
        scalar UMax_;
 
 
    // Protected Member Functions
 
        //- Constrain the given velocity fields by a given maximum value
        void addDamping(fvMatrix<vector>& eqn);
 
 
public:
 
    //- Runtime type information
    TypeName("velocityDampingConstraint");
 
 
    // Constructors
 
        //- Construct from components
        velocityDampingConstraint
        (
            const word& name,
            const word& modelType,
            const dictionary& dict,
            const fvMesh& mesh
        );
 
        //- No copy construct
        velocityDampingConstraint(const velocityDampingConstraint&) = delete;
 
        //- No copy assignment
        void operator=(const velocityDampingConstraint&) = delete;
 
 
    //- Destructor
    virtual ~velocityDampingConstraint() = default;
 
 
    // Member Functions
 
        // Set values directly
 
            //- Constrain vector matrix
            virtual void constrain(fvMatrix<vector>& eqn, const label fieldi);
 
 
        // I-O
 
            //- Write data
            virtual void writeData(Ostream& os) const;
 
            //- Read dictionary
            virtual bool read(const dictionary& dict);
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace fv
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //