Q.H

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-------------------------------------------------------------------------------
    Copyright (C) 2013-2016 OpenFOAM Foundation
    Copyright (C) 2016-2020 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::Q
 
Group
    grpFieldFunctionObjects
 
Description
    Computes the second invariant of
    the velocity gradient tensor \f$[s^{-2}]\f$.
 
    \f[
        \vec Q = \frac{1}{2}
        [ (tr (\nabla \vec U) )^2
        - tr (\nabla \vec U \cdot \nabla \vec U) ]
    \f]
 
    where
    \vartable
        \vec U       | velocity [m/s]
    \endvartable
 
    Operands:
    \table
      Operand        | Type           | Location
      input          | volVectorField | $FOAM_CASE/<time>/<inpField>
      output file    | -              | -
      output field   | volScalarField | $FOAM_CASE/<time>/<outField>
    \endtable
 
Usage
    Minimal example by using \c system/controlDict.functions:
    \verbatim
    Q1
    {
        // Mandatory entries (unmodifiable)
        type        Q;
        libs        (fieldFunctionObjects);
 
        // Optional (inherited) entries
        ...
    }
    \endverbatim
 
    where the entries mean:
    \table
      Property     | Description                        | Type | Req'd | Dflt
      type         | Type name: Q                       | word |  yes  | -
      libs         | Library name: fieldFunctionObjects | word |  yes  | -
    \endtable
 
    The inherited entries are elaborated in:
     - \link functionObject.H \endlink
     - \link fieldExpression.H \endlink
 
    Minimal example by using the \c postProcess utility:
    \verbatim
        postProcess -func Q
    \endverbatim
 
See also
    - Foam::functionObject
    - Foam::functionObjects::fieldExpression
    - Foam::functionObjects::fvMeshFunctionObject
    - ExtendedCodeGuide::functionObjects::field::Q
 
SourceFiles
    Q.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef functionObjects_Q_H
#define functionObjects_Q_H
 
#include "fieldExpression.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace functionObjects
{
 
/*---------------------------------------------------------------------------*\
                          Class Q Declaration
\*---------------------------------------------------------------------------*/
 
class Q
:
    public fieldExpression
{
    // Private Member Functions
 
        //- Calculate the Q field and return true if successful
        virtual bool calc();
 
 
public:
 
    //- Runtime type information
    TypeName("Q");
 
 
    // Constructors
 
        //- Construct from Time and dictionary
        Q
        (
            const word& name,
            const Time& runTime,
            const dictionary& dict
        );
 
        //- No copy construct
        Q(const Q&) = delete;
 
        //- No copy assignment
        void operator=(const Q&) = delete;
 
 
    //- Destructor
    virtual ~Q() = default;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace functionObjects
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //