externalWallHeatFluxTemperature: Changed Ta entry to Function1 to support time variation

Temporal variation of Ta is generally more useful than spatial variation but
a run-time switch between the two modes of operation could be implemented in
needed.

src/OpenFOAM/primitives/functions/Function1/Uniform/Uniform.C

@@ -0,0 +1,41 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 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 "Uniform.H"
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+template<class Type>
+Foam::Function1Types::Uniform<Type>::Uniform
+(
+    const word& entryName,
+    const dictionary& dict
+)
+:
+    Constant<Type>(entryName, dict)
+{}
+
+
+// ************************************************************************* //

src/OpenFOAM/primitives/functions/Function1/Uniform/Uniform.H

@@ -0,0 +1,98 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 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::Function1Types::Uniform
+
+Description
+    Templated function that returns a constant value.
+
+    Provides backward-compatibility for cases where a field is spatially
+    "uniform" and may be treated as a constant value.
+
+    Usage - for entry \<entryName\> returning the value <value>:
+    \verbatim
+        <entryName>    uniform  <value>
+    \endverbatim
+
+SourceFiles
+    Uniform.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Uniform_H
+#define Uniform_H
+
+#include "Function1.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace Function1Types
+{
+
+/*---------------------------------------------------------------------------*\
+                           Class Uniform Declaration
+\*---------------------------------------------------------------------------*/
+
+template<class Type>
+class Uniform
+:
+    public Constant<Type>
+{
+    // Private Member Functions
+
+        //- Disallow default bitwise assignment
+        void operator=(const Uniform<Type>&);
+
+
+public:
+
+    // Runtime type information
+    TypeName("uniform");
+
+
+    // Constructors
+
+        //- Construct from entry name and dictionary
+        Uniform(const word& entryName, const dictionary& dict);
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Function1Types
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#ifdef NoRepository
+    #include "Uniform.C"
+#endif
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/primitives/functions/Function1/makeFunction1s.C

@@ -41,6 +41,7 @@ License
 #define makeFunction1s(Type)                                                   \
     makeFunction1(Type);                                                       \
     makeFunction1Type(Constant, Type);                                         \
+    makeFunction1Type(Uniform, Type);                                          \
     makeFunction1Type(ZeroConstant, Type);                                     \
     makeFunction1Type(OneConstant, Type);                                      \
     makeFunction1Type(Polynomial, Type);                                       \