rigidBodyMeshMotion: displacementMotionSolver for the mesh-motion of multiple articulated rigid-bodies

The motion of the bodies is integrated using the rigidBodyDynamics
library with joints, restraints and external forces.

The mesh-motion is interpolated using septernion averaging.

This development is sponsored by Carnegie Wave Energy Ltd.

src/rigidBodyMeshMotion/Make/files

@@ -0,0 +1,3 @@
+rigidBodyMeshMotion.C
+
+LIB = $(FOAM_LIBBIN)/librigidBodyMeshMotion

src/rigidBodyMeshMotion/Make/options

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+EXE_INC = -ggdb3 -DFULLDEBUG \
+    -I$(LIB_SRC)/rigidBodyDynamics/lnInclude \
+    -I$(LIB_SRC)/finiteVolume/lnInclude \
+    -I$(LIB_SRC)/meshTools/lnInclude \
+    -I$(LIB_SRC)/postProcessing/functionObjects/forces/lnInclude \
+    -I$(LIB_SRC)/fileFormats/lnInclude \
+    -I$(LIB_SRC)/dynamicMesh/lnInclude
+
+LIB_LIBS = \
+    -lrigidBodyDynamics \
+    -lforces \
+    -lmeshTools \
+    -lfileFormats \
+    -ldynamicMesh

src/rigidBodyMeshMotion/rigidBodyMeshMotion.C

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+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2016 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 "rigidBodyMeshMotion.H"
+#include "addToRunTimeSelectionTable.H"
+#include "polyMesh.H"
+#include "pointPatchDist.H"
+#include "pointConstraints.H"
+#include "uniformDimensionedFields.H"
+#include "forces.H"
+#include "mathematicalConstants.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+    defineTypeNameAndDebug(rigidBodyMeshMotion, 0);
+
+    addToRunTimeSelectionTable
+    (
+        motionSolver,
+        rigidBodyMeshMotion,
+        dictionary
+    );
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::rigidBodyMeshMotion::bodyMesh::bodyMesh
+(
+    const polyMesh& mesh,
+    const word& name,
+    const label bodyID,
+    const dictionary& dict
+)
+:
+    name_(name),
+    bodyID_(bodyID),
+    patches_(wordReList(dict.lookup("patches"))),
+    patchSet_(mesh.boundaryMesh().patchSet(patches_)),
+    di_(readScalar(dict.lookup("innerDistance"))),
+    do_(readScalar(dict.lookup("outerDistance"))),
+    weight_
+    (
+        IOobject
+        (
+            name_ + ".motionScale",
+            mesh.time().timeName(),
+            mesh,
+            IOobject::NO_READ,
+            IOobject::NO_WRITE,
+            false
+        ),
+        pointMesh::New(mesh),
+        dimensionedScalar("zero", dimless, 0.0)
+    )
+{}
+
+
+Foam::rigidBodyMeshMotion::rigidBodyMeshMotion
+(
+    const polyMesh& mesh,
+    const IOdictionary& dict
+)
+:
+    displacementMotionSolver(mesh, dict, typeName),
+    model_
+    (
+        coeffDict(),
+        IOobject
+        (
+            "rigidBodyMotionState",
+            mesh.time().timeName(),
+            "uniform",
+            mesh
+        ).headerOk()
+      ? IOdictionary
+        (
+            IOobject
+            (
+                "rigidBodyMotionState",
+                mesh.time().timeName(),
+                "uniform",
+                mesh,
+                IOobject::READ_IF_PRESENT,
+                IOobject::NO_WRITE,
+                false
+            )
+        )
+      : coeffDict()
+    ),
+    test_(coeffDict().lookupOrDefault<Switch>("test", false)),
+    rhoInf_(1.0),
+    rhoName_(coeffDict().lookupOrDefault<word>("rhoName", "rho")),
+    curTimeIndex_(-1)
+{
+    if (rhoName_ == "rhoInf")
+    {
+        rhoInf_ = readScalar(coeffDict().lookup("rhoInf"));
+    }
+
+    const dictionary& bodiesDict = coeffDict().subDict("bodies");
+
+    forAllConstIter(IDLList<entry>, bodiesDict, iter)
+    {
+        const dictionary& bodyDict = iter().dict();
+
+        if (bodyDict.found("patches"))
+        {
+            bodyMeshes_.append
+            (
+                new bodyMesh
+                (
+                    mesh,
+                    iter().keyword(),
+                    model_.bodyID(iter().keyword()),
+                    bodyDict
+                )
+            );
+        }
+    }
+
+    // Calculate scaling factor everywhere for each meshed body
+    forAll(bodyMeshes_, bi)
+    {
+        const pointMesh& pMesh = pointMesh::New(mesh);
+
+        pointPatchDist pDist(pMesh, bodyMeshes_[bi].patchSet_, points0());
+
+        pointScalarField& scale = bodyMeshes_[bi].weight_;
+
+        // Scaling: 1 up to di then linear down to 0 at do away from patches
+        scale.internalField() =
+            min
+            (
+                max
+                (
+                    (bodyMeshes_[bi].do_ - pDist.internalField())
+                   /(bodyMeshes_[bi].do_ - bodyMeshes_[bi].di_),
+                    scalar(0)
+                ),
+                scalar(1)
+            );
+
+        // Convert the scale function to a cosine
+        scale.internalField() =
+            min
+            (
+                max
+                (
+                    0.5
+                  - 0.5
+                   *cos(scale.internalField()
+                   *Foam::constant::mathematical::pi),
+                    scalar(0)
+                ),
+                scalar(1)
+            );
+
+        pointConstraints::New(pMesh).constrain(scale);
+        //scale.write();
+    }
+}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::rigidBodyMeshMotion::~rigidBodyMeshMotion()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+Foam::tmp<Foam::pointField>
+Foam::rigidBodyMeshMotion::curPoints() const
+{
+    return points0() + pointDisplacement_.internalField();
+}
+
+
+void Foam::rigidBodyMeshMotion::solve()
+{
+    const Time& t = mesh().time();
+
+    if (mesh().nPoints() != points0().size())
+    {
+        FatalErrorInFunction
+            << "The number of points in the mesh seems to have changed." << endl
+            << "In constant/polyMesh there are " << points0().size()
+            << " points; in the current mesh there are " << mesh().nPoints()
+            << " points." << exit(FatalError);
+    }
+
+    // Store the motion state at the beginning of the time-step
+    if (curTimeIndex_ != this->db().time().timeIndex())
+    {
+        model_.newTime();
+        curTimeIndex_ = this->db().time().timeIndex();
+    }
+
+    dimensionedVector g("g", dimAcceleration, vector::zero);
+
+    if (db().foundObject<uniformDimensionedVectorField>("g"))
+    {
+        g = db().lookupObject<uniformDimensionedVectorField>("g");
+    }
+    else if (coeffDict().found("g"))
+    {
+        coeffDict().lookup("g") >> g;
+    }
+
+    model_.g() = g.value();
+
+    if (test_)
+    {
+        label nIter(readLabel(coeffDict().lookup("nIter")));
+
+        for (label i=0; i<nIter; i++)
+        {
+            model_.solve
+            (
+                t.deltaTValue(),
+                scalarField(model_.nDoF(), Zero),
+                Field<spatialVector>(model_.nBodies(), Zero)
+            );
+        }
+    }
+    else
+    {
+        Field<spatialVector> fx(model_.nBodies(), Zero);
+
+        forAll(bodyMeshes_, bi)
+        {
+            const label bodyID = bodyMeshes_[bi].bodyID_;
+
+            dictionary forcesDict;
+
+            forcesDict.add("type", forces::typeName);
+            forcesDict.add("patches", bodyMeshes_[bi].patches_);
+            forcesDict.add("rhoInf", rhoInf_);
+            forcesDict.add("rhoName", rhoName_);
+            forcesDict.add("CofR", model_.X0(bodyID).r());
+
+            forces f("forces", db(), forcesDict);
+
+            f.calcForcesMoment();
+
+            fx[bodyID].l() = f.forceEff();
+            fx[bodyID].w() = f.momentEff();
+        }
+
+        model_.solve
+        (
+            t.deltaTValue(),
+            scalarField(model_.nDoF(), Zero),
+            fx
+        );
+    }
+
+
+    // Update the displacements
+    if (bodyMeshes_.size() == 1)
+    {
+        pointDisplacement_.internalField() = model_.transformPoints
+        (
+            bodyMeshes_[0].bodyID_,
+            bodyMeshes_[0].weight_,
+            points0()
+        ) - points0();
+    }
+    else
+    {
+        labelList bodyIDs(bodyMeshes_.size());
+        List<const scalarField*> weights(bodyMeshes_.size());
+        forAll(bodyIDs, bi)
+        {
+            bodyIDs[bi] = bodyMeshes_[bi].bodyID_;
+            weights[bi] = &bodyMeshes_[bi].weight_;
+        }
+
+        pointDisplacement_.internalField() =
+            model_.transformPoints(bodyIDs, weights, points0()) - points0();
+    }
+
+    // Displacement has changed. Update boundary conditions
+    pointConstraints::New
+    (
+        pointDisplacement_.mesh()
+    ).constrainDisplacement(pointDisplacement_);
+}
+
+
+bool Foam::rigidBodyMeshMotion::writeObject
+(
+    IOstream::streamFormat fmt,
+    IOstream::versionNumber ver,
+    IOstream::compressionType cmp
+) const
+{
+    IOdictionary dict
+    (
+        IOobject
+        (
+            "rigidBodyMotionState",
+            mesh().time().timeName(),
+            "uniform",
+            mesh(),
+            IOobject::NO_READ,
+            IOobject::NO_WRITE,
+            false
+        )
+    );
+
+    model_.state().write(dict);
+    return dict.regIOobject::write();
+}
+
+
+bool Foam::rigidBodyMeshMotion::read()
+{
+    if (displacementMotionSolver::read())
+    {
+        model_.read(coeffDict());
+
+        return true;
+    }
+    else
+    {
+        return false;
+    }
+}
+
+
+// ************************************************************************* //

src/rigidBodyMeshMotion/rigidBodyMeshMotion.H

@@ -0,0 +1,184 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2016 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::rigidBodyMeshMotion
+
+Description
+    Rigid-body mesh motion solver for fvMesh.
+
+    Applies septernion interpolation of movement as function of distance to the
+    object surface.
+
+SourceFiles
+    rigidBodyMeshMotion.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef rigidBodyMeshMotion_H
+#define rigidBodyMeshMotion_H
+
+#include "displacementMotionSolver.H"
+#include "rigidBodyMotion.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+/*---------------------------------------------------------------------------*\
+        Class rigidBodyMeshMotion Declaration
+\*---------------------------------------------------------------------------*/
+
+class rigidBodyMeshMotion
+:
+    public displacementMotionSolver
+{
+    //- Class containing the patches and point motion weighting for each body
+    class bodyMesh
+    {
+        //- Name of the body
+        const word name_;
+
+        //- ID of the body in the RBD::rigidBodyMotion
+        const label bodyID_;
+
+        //- List of mesh patches associated with this body
+        const wordReList patches_;
+
+        //- Patches to integrate forces
+        const labelHashSet patchSet_;
+
+        //- Inner morphing distance (limit of solid-body region)
+        const scalar di_;
+
+        //- Outer morphing distance (limit of linear interpolation region)
+        const scalar do_;
+
+        //- Current interpolation weight
+        //  (1 at patches and within di_, 0 at do_ and beyond)
+        pointScalarField weight_;
+
+
+    public:
+
+        friend class rigidBodyMeshMotion;
+
+        bodyMesh
+        (
+            const polyMesh& mesh,
+            const word& name,
+            const label bodyID,
+            const dictionary& dict
+        );
+    };
+
+
+    // Private data
+
+        //- Rigid-body model
+        RBD::rigidBodyMotion model_;
+
+        //- List of the bodyMeshes containing the patches and point motion
+        //  weighting for each body
+        PtrList<bodyMesh> bodyMeshes_;
+
+        //- Switch for test-mode in which only the
+        //  gravitational body-force is applied
+        Switch test_;
+
+        //- Reference density required by the forces object for
+        //  incompressible calculations, required if rhoName == rhoInf
+        scalar rhoInf_;
+
+        //- Name of density field, optional unless used for an
+        //  incompressible simulation, when this needs to be specified
+        //  as rhoInf
+        word rhoName_;
+
+        //- Current time index (used for updating)
+        label curTimeIndex_;
+
+
+    // Private Member Functions
+
+        //- Disallow default bitwise copy construct
+        rigidBodyMeshMotion
+        (
+            const rigidBodyMeshMotion&
+        );
+
+        //- Disallow default bitwise assignment
+        void operator=(const rigidBodyMeshMotion&);
+
+
+public:
+
+    //- Runtime type information
+    TypeName("rigidBodyMotion");
+
+
+    // Constructors
+
+        //- Construct from polyMesh and IOdictionary
+        rigidBodyMeshMotion
+        (
+            const polyMesh&,
+            const IOdictionary& dict
+        );
+
+
+    //- Destructor
+    ~rigidBodyMeshMotion();
+
+
+    // Member Functions
+
+        //- Return point location obtained from the current motion field
+        virtual tmp<pointField> curPoints() const;
+
+        //- Solve for motion
+        virtual void solve();
+
+        //- Write state using given format, version and compression
+        virtual bool writeObject
+        (
+            IOstream::streamFormat fmt,
+            IOstream::versionNumber ver,
+            IOstream::compressionType cmp
+        ) const;
+
+        //- Read dynamicMeshDict dictionary
+        virtual bool read();
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //