constantThermophysicalFunction: New constant liquid property function

Usage
    \constant
        Property    | Description
        value       | Constant property value
    \endconstant

    Example for the density of water between 280 and 350K
    \verbatim
    rho
    {
        type    constant;
        value   999.87;
    }
    \endverbatim

src/thermophysicalModels/thermophysicalProperties/Make/files

@@ -1,6 +1,7 @@
 thermophysicalFunctions/thermophysicalFunction/thermophysicalFunction.C
 
 thermophysicalFunctions/none/noneThermophysicalFunction.C
+thermophysicalFunctions/constant/constantThermophysicalFunction.C
 thermophysicalFunctions/table/tableThermophysicalFunction.C
 thermophysicalFunctions/APIfunctions/APIdiffCoef/APIdiffCoefThermophysicalFunction.C
 

src/thermophysicalModels/thermophysicalProperties/thermophysicalFunctions/constant/constantThermophysicalFunction.C

@@ -0,0 +1,80 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2019 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 "constantThermophysicalFunction.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace thermophysicalFunctions
+{
+    defineTypeNameAndDebug(constant, 0);
+    addToRunTimeSelectionTable(thermophysicalFunction, constant, dictionary);
+}
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::thermophysicalFunctions::constant::constant(const dictionary& dict)
+:
+    value_(dict.lookupType<scalar>("value"))
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+Foam::scalar Foam::thermophysicalFunctions::constant::f
+(
+    scalar p,
+    scalar T
+) const
+{
+    return value_;
+}
+
+
+void Foam::thermophysicalFunctions::constant::writeData(Ostream& os) const
+{
+    os  << value_ << token::SPACE;
+}
+
+
+// * * * * * * * * * * * * * * IOStream operators  * * * * * * * * * * * * * //
+
+Foam::Ostream& Foam::thermophysicalFunctions::operator<<
+(
+    Ostream& os,
+    const constant& f
+)
+{
+    f.writeData(os);
+    return os;
+}
+
+
+// ************************************************************************* //

src/thermophysicalModels/thermophysicalProperties/thermophysicalFunctions/constant/constantThermophysicalFunction.H

@@ -0,0 +1,114 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2019 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/>.
+
+Class
+    Foam::thermophysicalFunctions::constant
+
+Description
+    Constant property function.
+
+Usage
+    \constant
+        Property    | Description
+        value       | Constant property value
+    \endconstant
+
+    Example for the density of water between 280 and 350K
+    \verbatim
+    rho
+    {
+        type    constant;
+        value   999.87;
+    }
+    \endverbatim
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef constantThermophysicalFunction_H
+#define constantThermophysicalFunction_H
+
+#include "thermophysicalFunction.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace thermophysicalFunctions
+{
+
+// Forward declaration of friend functions and operators
+class constant;
+Ostream& operator<<(Ostream& os, const constant& f);
+
+
+/*---------------------------------------------------------------------------*\
+                           Class constant Declaration
+\*---------------------------------------------------------------------------*/
+
+class constant
+:
+    public thermophysicalFunction
+{
+    // Private member data
+
+        //- Constant value
+        scalar value_;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("constant");
+
+
+    // Constructors
+
+        //- Construct from dictionary
+        constant(const dictionary& dict);
+
+
+    // Member Functions
+
+        //- Evaluate the function and return the result
+        scalar f(scalar p, scalar T) const;
+
+        //- Write the function coefficients
+        void writeData(Ostream& os) const;
+
+
+    // Ostream Operator
+
+        friend Ostream& operator<<(Ostream& os, const constant& f);
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace thermophysicalFunctions
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //