data/src/functionObjects/field/pressure/pressure.C

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2012-2026 OpenFOAM Foundation
     \\/     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 "pressure.H"
#include "volFields.H"
#include "addToRunTimeSelectionTable.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

namespace Foam
{
namespace functionObjects
{
    defineTypeNameAndDebug(pressure, 0);
    addToRunTimeSelectionTable(functionObject, pressure, dictionary);
}
}


// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //

Foam::word Foam::functionObjects::pressure::resultName() const
{
    word rName;

    if (calcTotal_)
    {
        rName = "total(" + fieldName_ + ")";
    }
    else
    {
        rName = "static(" + fieldName_ + ")";
    }

    if (calcCoeff_)
    {
        rName += "_coeff";
    }

    return rName;
}


Foam::tmp<Foam::volScalarField> Foam::functionObjects::pressure::rhoScale
(
    const volScalarField& p
) const
{
    if (p.dimensions() == dimensions::pressure)
    {
        return p;
    }
    else
    {
        return dimensionedScalar("rhoInf", dimensions::density, rhoInf_)*p;
    }
}


Foam::tmp<Foam::volScalarField> Foam::functionObjects::pressure::rhoScale
(
    const volScalarField& p,
    const tmp<volScalarField>& tsf
) const
{
    if (p.dimensions() == dimensions::pressure)
    {
        return lookupObject<volScalarField>(rhoName_)*tsf;
    }
    else
    {
        return dimensionedScalar("rhoInf", dimensions::density, rhoInf_)*tsf;
    }
}


Foam::tmp<Foam::volScalarField> Foam::functionObjects::pressure::pRef
(
    const tmp<volScalarField>& tp
) const
{
    if (calcTotal_)
    {
        return tp + dimensionedScalar("pRef", dimensions::pressure, pRef_);
    }
    else
    {
        return move(tp);
    }
}


Foam::tmp<Foam::volScalarField> Foam::functionObjects::pressure::pDyn
(
    const volScalarField& p,
    const tmp<volScalarField>& tp
) const
{
    if (calcTotal_)
    {
        return
            tp + rhoScale(p, 0.5*magSqr(lookupObject<volVectorField>(UName_)));
    }
    else
    {
        return move(tp);
    }
}


Foam::tmp<Foam::volScalarField>
Foam::functionObjects::pressure::coeff
(
    const tmp<volScalarField>& tp
) const
{
    if (calcCoeff_)
    {
        tmp<volScalarField> tpCoeff(tp.ptr());
        volScalarField& pCoeff = tpCoeff.ref();

        pCoeff -= dimensionedScalar("pInf", dimensions::pressure, pInf_);

        const dimensionedScalar pSmall("pSmall", dimensions::pressure, small);
        const dimensionedVector U("U", dimensions::velocity, UInf_);
        const dimensionedScalar rho("rho", dimensions::density, rhoInf_);

        pCoeff /= 0.5*rho*magSqr(U) + pSmall;

        return tpCoeff;
    }
    else
    {
        return move(tp);
    }
}


// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //

bool Foam::functionObjects::pressure::calc()
{
    if (foundObject<volScalarField>(fieldName_))
    {
        const volScalarField& p = lookupObject<volScalarField>(fieldName_);

        store
        (
            resultName_,
            volScalarField::New(resultName_, coeff(pRef(pDyn(p, rhoScale(p)))))
        );

        return true;
    }
    else
    {
        cannotFindObject<volScalarField>(fieldName_);

        return false;
    }
}


// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::functionObjects::pressure::pressure
(
    const word& name,
    const Time& runTime,
    const dictionary& dict
)
:
    fieldExpression(name, runTime, dict, typeName, "p"),
    UName_("U"),
    rhoName_("rho"),
    calcTotal_(false),
    pRef_(0),
    calcCoeff_(false),
    pInf_(0),
    UInf_(Zero),
    rhoInf_(1)
{
    read(dict);

    dimensionSet pDims(dimensions::pressure);

    if (calcCoeff_)
    {
        pDims /= dimensions::pressure;
    }
}


// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //

Foam::functionObjects::pressure::~pressure()
{}


// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

bool Foam::functionObjects::pressure::read(const dictionary& dict)
{
    dict.readIfPresent("U", UName_);
    dict.readIfPresent("rho", rhoName_);

    if (rhoName_ == "rhoInf")
    {
        dict.lookup("rhoInf") >> rhoInf_;
    }

    dict.lookup("calcTotal") >> calcTotal_;
    if (calcTotal_)
    {
        dict.lookup("pRef") >> pRef_;
    }

    dict.lookup("calcCoeff") >> calcCoeff_;
    if (calcCoeff_)
    {
        dict.lookup("pInf") >> pInf_;
        dict.lookup("UInf") >> UInf_;
        dict.lookup("rhoInf") >> rhoInf_;

        scalar zeroCheck = 0.5*rhoInf_*magSqr(UInf_) + pInf_;

        if (mag(zeroCheck) < rootVSmall)
        {
            WarningInFunction
                << type() << " " << name() << ": "
                << "Coefficient calculation requested, but reference "
                << "pressure level is zero.  Please check the supplied "
                << "values of pInf, UInf and rhoInf" << endl;
        }
    }

    resultName_ = dict.lookupOrDefault<word>("result", resultName());

    return true;
}


// ************************************************************************* //