functionObjects/field: Added interfaceHeight

This function object reports the height of the interface above a set of
locations. It writes the height above the location, above the boundary,
and the point on the interface. It uses an integral approach, so if
there are multiple interfaces above or below a location, this method
will compute an average.

It can be enabled with the following entry in the system/controlDict:

    functions
    {
        interfaceHeight1
        {
            type           interfaceHeight;
            libs           ("libfieldFunctionObjects.so");
            alpha          alpha.water;
            locations      ((0 0 0) (10 0 0) (20 0 0));
        }
    }

This work was supported by Jan Kaufmann and Jan Oberhagemann at DNV GL.

src/functionObjects/field/Make/files

@@ -60,4 +60,6 @@ fieldsExpression/fieldsExpression.C
 add/add.C
 subtract/subtract.C
 
+interfaceHeight/interfaceHeight.C
+
 LIB = $(FOAM_LIBBIN)/libfieldFunctionObjects

src/functionObjects/field/interfaceHeight/interfaceHeight.C

@@ -0,0 +1,277 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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 "interfaceHeight.H"
+#include "fvMesh.H"
+#include "interpolation.H"
+#include "IOmanip.H"
+#include "meshSearch.H"
+#include "midPointAndFaceSet.H"
+#include "Time.H"
+#include "uniformDimensionedFields.H"
+#include "volFields.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionObjects
+{
+    defineTypeNameAndDebug(interfaceHeight, 0);
+    addToRunTimeSelectionTable(functionObject, interfaceHeight, dictionary);
+}
+}
+
+
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+void Foam::functionObjects::interfaceHeight::writePositions()
+{
+    const uniformDimensionedVectorField& g =
+        mesh_.lookupObject<uniformDimensionedVectorField>("g");
+    const vector gHat = g.value()/mag(g.value());
+
+    const volScalarField& alpha =
+        mesh_.lookupObject<volScalarField>(alphaName_);
+
+    autoPtr<interpolation<scalar>>
+        interpolator
+        (
+            interpolation<scalar>::New(interpolationScheme_, alpha)
+        );
+
+    if (Pstream::master())
+    {
+        writeTime(file(HEIGHT_FILE));
+        writeTime(file(POSITION_FILE));
+    }
+
+    forAll(locations_, li)
+    {
+        // Create a set along a ray projected in the direction of gravity
+        const midPointAndFaceSet set
+        (
+            "",
+            mesh_,
+            meshSearch(mesh_),
+            "xyz",
+            locations_[li] + gHat*mesh_.bounds().mag(),
+            locations_[li] - gHat*mesh_.bounds().mag()
+        );
+
+        // Find the height of the location above the boundary
+        scalar hLB = set.size() ? - gHat & (locations_[li] - set[0]) : - VGREAT;
+        reduce(hLB, maxOp<scalar>());
+
+        // Calculate the integrals of length and length*alpha along the sampling
+        // line. The latter is equal to the equivalent length with alpha equal
+        // to one.
+        scalar sumLength = 0, sumLengthAlpha = 0;
+        for(label si = 0; si < set.size() - 1; ++ si)
+        {
+            if (set.segments()[si] != set.segments()[si+1])
+            {
+                continue;
+            }
+
+            const vector& p0 = set[si], p1 = set[si+1];
+            const label c0 = set.cells()[si], c1 = set.cells()[si+1];
+            const label f0 = set.faces()[si], f1 = set.faces()[si+1];
+            const scalar a0 = interpolator->interpolate(p0, c0, f0);
+            const scalar a1 = interpolator->interpolate(p1, c1, f1);
+
+            const scalar l = - gHat & (p1 - p0);
+            sumLength += l;
+            sumLengthAlpha += l*(a0 + a1)/2;
+        }
+
+        reduce(sumLength, sumOp<scalar>());
+        reduce(sumLengthAlpha, sumOp<scalar>());
+
+        // Write out
+        if (Pstream::master())
+        {
+            // Interface heights above the boundary and location
+            const scalar hIB =
+                liquid_ ? sumLengthAlpha : sumLength - sumLengthAlpha;
+            const scalar hIL = hIB - hLB;
+
+            // Position of the interface
+            const point p = locations_[li] - gHat*hIL;
+
+            const Foam::Omanip<int> w = valueWidth(1);
+
+            file(HEIGHT_FILE) << w << hIB << w << hIL;
+            file(POSITION_FILE) << '(' << w << p.x() << w << p.y()
+                << valueWidth() << p.z() << ") ";
+        }
+    }
+
+    if (Pstream::master())
+    {
+        file(HEIGHT_FILE).endl();
+        file(POSITION_FILE).endl();
+    }
+}
+
+
+// * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * * //
+
+void Foam::functionObjects::interfaceHeight::writeFileHeader(const label i)
+{
+    forAll(locations_, li)
+    {
+        writeHeaderValue
+        (
+            file(i),
+            "Location " + Foam::name(li),
+            locations_[li]
+        );
+    }
+
+    switch (fileID(i))
+    {
+        case HEIGHT_FILE:
+            writeHeaderValue
+            (
+                file(i),
+                "hB",
+                "Interface height above the boundary"
+            );
+            writeHeaderValue
+            (
+                file(i),
+                "hL",
+                "Interface height above the location"
+            );
+            break;
+        case POSITION_FILE:
+            writeHeaderValue(file(i), "p", "Interface position");
+            break;
+    }
+
+    const Foam::Omanip<int> w = valueWidth(1);
+
+    writeCommented(file(i), "Location");
+    forAll(locations_, li)
+    {
+        switch (fileID(i))
+        {
+            case HEIGHT_FILE:
+                file(i) << w << li << w << ' ';
+                break;
+            case POSITION_FILE:
+                file(i) << w << li << w << ' ' << w << ' ' << "  ";
+                break;
+        }
+    }
+    file(i).endl();
+
+    writeCommented(file(i), "Time");
+    forAll(locations_, li)
+    {
+        switch (fileID(i))
+        {
+            case HEIGHT_FILE:
+                file(i) << w << "hB" << w << "hL";
+                break;
+            case POSITION_FILE:
+                file(i) << w << "p" << w << ' ' << w << ' ' << "  ";
+                break;
+        }
+    }
+    file(i).endl();
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::interfaceHeight::interfaceHeight
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fvMeshFunctionObject(name, runTime, dict),
+    logFiles(mesh_, name),
+    alphaName_("alpha"),
+    liquid_(true),
+    locations_(),
+    interpolationScheme_("cellPoint")
+{
+    read(dict);
+
+    wordList names(2);
+    names[HEIGHT_FILE] = "height";
+    names[POSITION_FILE] = "position";
+
+    resetNames(wordList(names));
+}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::functionObjects::interfaceHeight::~interfaceHeight()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+bool Foam::functionObjects::interfaceHeight::read(const dictionary& dict)
+{
+    dict.readIfPresent("alpha", alphaName_);
+    dict.readIfPresent("liquid", liquid_);
+    dict.lookup("locations") >> locations_;
+    dict.readIfPresent("interpolationScheme", interpolationScheme_);
+
+    return true;
+}
+
+
+bool Foam::functionObjects::interfaceHeight::execute()
+{
+    return true;
+}
+
+
+bool Foam::functionObjects::interfaceHeight::end()
+{
+    return true;
+}
+
+
+bool Foam::functionObjects::interfaceHeight::write()
+{
+    logFiles::write();
+
+    writePositions();
+
+    return true;
+}
+
+
+// ************************************************************************* //