ENC: sixDoFRigidBodyMotion. Adding fixedAxis constraint.

src/postProcessing/functionObjects/forces/Make/files

@@ -15,18 +15,19 @@ sDoFRBMR = $(sDoFRBM)/sixDoFRigidBodyMotionRestraint
 
 $(sDoFRBMR)/sixDoFRigidBodyMotionRestraint/sixDoFRigidBodyMotionRestraint.C
 $(sDoFRBMR)/sixDoFRigidBodyMotionRestraint/newSixDoFRigidBodyMotionRestraint.C
+$(sDoFRBMR)/linearAxialAngularSpring/linearAxialAngularSpring.C
 $(sDoFRBMR)/linearSpring/linearSpring.C
 $(sDoFRBMR)/sphericalAngularSpring/sphericalAngularSpring.C
-$(sDoFRBMR)/linearAxialAngularSpring/linearAxialAngularSpring.C
 
 sDoFRBMC = $(sDoFRBM)/sixDoFRigidBodyMotionConstraint
 
 $(sDoFRBMC)/sixDoFRigidBodyMotionConstraint/sixDoFRigidBodyMotionConstraint.C
 $(sDoFRBMC)/sixDoFRigidBodyMotionConstraint/newSixDoFRigidBodyMotionConstraint.C
-$(sDoFRBMC)/fixedPoint/fixedPoint.C
-$(sDoFRBMC)/fixedPlane/fixedPlane.C
+$(sDoFRBMC)/fixedAxis/fixedAxis.C
 $(sDoFRBMC)/fixedLine/fixedLine.C
 $(sDoFRBMC)/fixedOrientation/fixedOrientation.C
+$(sDoFRBMC)/fixedPlane/fixedPlane.C
+$(sDoFRBMC)/fixedPoint/fixedPoint.C
 
 pointPatchFields/derived/sixDoFRigidBodyDisplacement/sixDoFRigidBodyDisplacementPointPatchVectorField.C
 pointPatchFields/derived/uncoupledSixDoFRigidBodyDisplacement/uncoupledSixDoFRigidBodyDisplacementPointPatchVectorField.C

src/postProcessing/functionObjects/forces/pointPatchFields/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion.C

@@ -54,6 +54,8 @@ void Foam::sixDoFRigidBodyMotion::applyRestraints()
 
             a() += rF/mass_;
 
+            // Moments are returned in global axes, transforming to
+            // body local to add to torque.
             tau() += Q().T() & (rM + ((rP - centreOfMass()) ^ rF));
         }
     }
@@ -137,7 +139,8 @@ void Foam::sixDoFRigidBodyMotion::applyConstraints(scalar deltaT)
         a() += cFA/mass_;
 
         // The moment of constraint forces has already been added
-        // during accumulation
+        // during accumulation.  Moments are returned in global axes,
+        // transforming to body local
         tau() += Q().T() & cMA;
     }
 }

src/postProcessing/functionObjects/forces/pointPatchFields/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion.H

@@ -272,7 +272,12 @@ public:
 
         //- Transform the given reference state direction by the current
         //  motion state
-        inline point currentOrientation(const vector& refDir) const;
+        inline vector currentOrientation(const vector& refDir) const;
+
+        //- Access the orientation tensor, Q.
+        //  globalVector = Q & bodyLocalVector
+        //  bodyLocalVector = Q.T() & globalVector
+        inline const tensor& currentOrientation() const;
 
         //- Predict the position of the supplied point after deltaT
         //  given the current motion state and the additional supplied

src/postProcessing/functionObjects/forces/pointPatchFields/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotionConstraint/fixedAxis/fixedAxis.C

@@ -0,0 +1,157 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 1991-2009 OpenCFD Ltd.
+     \\/     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 2 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, write to the Free Software Foundation,
+    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+\*---------------------------------------------------------------------------*/
+
+#include "fixedAxis.H"
+#include "addToRunTimeSelectionTable.H"
+#include "sixDoFRigidBodyMotion.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace sixDoFRigidBodyMotionConstraints
+{
+    defineTypeNameAndDebug(fixedAxis, 0);
+    addToRunTimeSelectionTable
+    (
+        sixDoFRigidBodyMotionConstraint,
+        fixedAxis,
+        dictionary
+    );
+};
+};
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::sixDoFRigidBodyMotionConstraints::fixedAxis::fixedAxis
+(
+    const dictionary& sDoFRBMCDict
+)
+:
+    sixDoFRigidBodyMotionConstraint(sDoFRBMCDict),
+    fixedAxis_()
+{
+    read(sDoFRBMCDict);
+}
+
+
+// * * * * * * * * * * * * * * * * Destructors * * * * * * * * * * * * * * * //
+
+Foam::sixDoFRigidBodyMotionConstraints::fixedAxis::~fixedAxis()
+{}
+
+
+// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
+
+bool Foam::sixDoFRigidBodyMotionConstraints::fixedAxis::constrain
+(
+    const sixDoFRigidBodyMotion& motion,
+    const vector& existingConstraintForce,
+    const vector& existingConstraintMoment,
+    scalar deltaT,
+    vector& constraintPosition,
+    vector& constraintForceIncrement,
+    vector& constraintMomentIncrement
+) const
+{
+    constraintMomentIncrement = vector::zero;
+
+    vector predictedDir = motion.predictedOrientation
+    (
+        fixedAxis_,
+        existingConstraintMoment,
+        deltaT
+    );
+
+    scalar theta = acos(predictedDir & fixedAxis_);
+
+    vector rotationAxis = fixedAxis_ ^ predictedDir;
+
+    scalar magRotationAxis = mag(rotationAxis);
+
+    if (magRotationAxis > VSMALL)
+    {
+        rotationAxis /= magRotationAxis;
+
+        const tensor& Q = motion.currentOrientation();
+
+        // Transform rotationAxis to body local system
+        rotationAxis = Q.T() & rotationAxis;
+
+        constraintMomentIncrement =
+           -relaxationFactor_
+           *(motion.momentOfInertia() & rotationAxis)
+           *theta/sqr(deltaT);
+
+        // Transform moment increment to global system
+        constraintMomentIncrement = Q & constraintMomentIncrement;
+
+        // Remove any moment that is around the fixedAxis_
+        constraintMomentIncrement -=
+            (constraintMomentIncrement & fixedAxis_)*fixedAxis_;
+    }
+
+    constraintPosition = motion.centreOfMass();
+
+    constraintForceIncrement = vector::zero;
+
+    return (mag(theta) < tolerance_);
+}
+
+
+bool Foam::sixDoFRigidBodyMotionConstraints::fixedAxis::read
+(
+    const dictionary& sDoFRBMCDict
+)
+{
+    sixDoFRigidBodyMotionConstraint::read(sDoFRBMCDict);
+
+    sDoFRBMCCoeffs_.lookup("axis") >> fixedAxis_;
+
+    scalar magFixedAxis(mag(fixedAxis_));
+
+    if (magFixedAxis > VSMALL)
+    {
+        fixedAxis_ /= magFixedAxis;
+    }
+    else
+    {
+        FatalErrorIn
+        (
+            "Foam::sixDoFRigidBodyMotionConstraints::fixedAxis::read"
+            "("
+                "const dictionary& sDoFRBMCDict"
+            ")"
+        )
+            << "axis has zero length"
+            << abort(FatalError);
+    }
+
+    return true;
+}
+
+// ************************************************************************* //

src/postProcessing/functionObjects/forces/pointPatchFields/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotionConstraint/fixedAxis/fixedAxis.H

@@ -0,0 +1,126 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 1991-2009 OpenCFD Ltd.
+     \\/     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 2 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, write to the Free Software Foundation,
+    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+Class
+    Foam::sixDoFRigidBodyMotionConstraints::fixedAxis
+
+Description
+    sixDoFRigidBodyMotionConstraint.  Axis of body fixed global
+    space.
+
+SourceFiles
+    fixedAxis.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef fixedAxis_H
+#define fixedAxis_H
+
+#include "sixDoFRigidBodyMotionConstraint.H"
+#include "point.H"
+#include "tensor.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+namespace sixDoFRigidBodyMotionConstraints
+{
+
+/*---------------------------------------------------------------------------*\
+                            Class fixedAxis Declaration
+\*---------------------------------------------------------------------------*/
+
+class fixedAxis
+:
+    public sixDoFRigidBodyMotionConstraint
+{
+
+    // Private data
+
+        //- Reference axis in global space
+        vector fixedAxis_;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("fixedAxis");
+
+
+    // Constructors
+
+        //- Construct from components
+        fixedAxis
+        (
+            const dictionary& sDoFRBMCDict
+        );
+
+        //- Construct and return a clone
+        virtual autoPtr<sixDoFRigidBodyMotionConstraint> clone() const
+        {
+            return autoPtr<sixDoFRigidBodyMotionConstraint>
+            (
+                new fixedAxis(*this)
+            );
+        }
+
+
+    // Destructor
+
+        virtual ~fixedAxis();
+
+
+    // Member Functions
+
+        //- Calculate the constraint position, force and moment.
+        //  Global reference frame vectors.  Returns boolean stating
+        //  whether the constraint been converged to tolerance.
+        virtual bool constrain
+        (
+            const sixDoFRigidBodyMotion& motion,
+            const vector& existingConstraintForce,
+            const vector& existingConstraintMoment,
+            scalar deltaT,
+            vector& constraintPosition,
+            vector& constraintForceIncrement,
+            vector& constraintMomentIncrement
+        ) const;
+
+        //- Update properties from given dictionary
+        virtual bool read(const dictionary& sDoFRBMCCoeff);
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace solidBodyMotionFunctions
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/postProcessing/functionObjects/forces/pointPatchFields/derived/sixDoFRigidBodyMotion/sixDoFRigidBodyMotionI.H

@@ -210,7 +210,7 @@ inline Foam::point Foam::sixDoFRigidBodyMotion::currentPosition
 }
 
 
-inline Foam::point Foam::sixDoFRigidBodyMotion::currentOrientation
+inline Foam::vector Foam::sixDoFRigidBodyMotion::currentOrientation
 (
     const vector& refDir
 ) const
@@ -219,6 +219,13 @@ inline Foam::point Foam::sixDoFRigidBodyMotion::currentOrientation
 }
 
 
+inline const Foam::tensor&
+Foam::sixDoFRigidBodyMotion::currentOrientation() const
+{
+    return Q();
+}
+
+
 inline Foam::vector Foam::sixDoFRigidBodyMotion::omega() const
 {
     return  Q() & (inv(momentOfInertia_) & pi());