sphericalAngularSpring.C

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    Copyright (C) 2011-2016 OpenFOAM Foundation
    Copyright (C) 2018-2020 OpenCFD Ltd.
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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.
 
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
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#include "sphericalAngularSpring.H"
#include "addToRunTimeSelectionTable.H"
#include "sixDoFRigidBodyMotion.H"
 
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
namespace Foam
{
namespace sixDoFRigidBodyMotionRestraints
{
    defineTypeNameAndDebug(sphericalAngularSpring, 0);
 
    addToRunTimeSelectionTable
    (
        sixDoFRigidBodyMotionRestraint,
        sphericalAngularSpring,
        dictionary
    );
}
}
 
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
Foam::sixDoFRigidBodyMotionRestraints::sphericalAngularSpring::
sphericalAngularSpring
(
    const word& name,
    const dictionary& sDoFRBMRDict
)
:
    sixDoFRigidBodyMotionRestraint(name, sDoFRBMRDict),
    refQ_(),
    stiffness_(),
    damping_()
{
    read(sDoFRBMRDict);
}
 
 
// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
Foam::sixDoFRigidBodyMotionRestraints::sphericalAngularSpring::
~sphericalAngularSpring()
{}
 
 
// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
 
void Foam::sixDoFRigidBodyMotionRestraints::sphericalAngularSpring::restrain
(
    const sixDoFRigidBodyMotion& motion,
    vector& restraintPosition,
    vector& restraintForce,
    vector& restraintMoment
) const
{
    restraintMoment = Zero;
 
    for (direction cmpt=0; cmpt<vector::nComponents; cmpt++)
    {
        vector axis = Zero;
        axis[cmpt] = 1;
 
        vector refDir = Zero;
        refDir[(cmpt + 1) % 3] = 1;
 
        vector newDir = motion.orientation() & refDir;
 
        axis = (refQ_ & axis);
        refDir = (refQ_ & refDir);
        newDir -= (axis & newDir)*axis;
 
        restraintMoment += -stiffness_*(refDir ^ newDir);
    }
 
    restraintMoment += -damping_*motion.omega();
 
    restraintForce = Zero;
 
    // Not needed to be altered as restraintForce is zero, but set to
    // centreOfRotation to be sure of no spurious moment
    restraintPosition = motion.centreOfRotation();
 
    if (motion.report())
    {
        Info<< " moment " << restraintMoment
            << endl;
    }
}
 
 
bool Foam::sixDoFRigidBodyMotionRestraints::sphericalAngularSpring::read
(
    const dictionary& sDoFRBMRDict
)
{
    sixDoFRigidBodyMotionRestraint::read(sDoFRBMRDict);
 
    refQ_ = sDoFRBMRCoeffs_.getOrDefault<tensor>("referenceOrientation", I);
 
    if (mag(mag(refQ_) - sqrt(3.0)) > ROOTSMALL)
    {
        FatalErrorInFunction
            << "referenceOrientation " << refQ_ << " is not a rotation tensor. "
            << "mag(referenceOrientation) - sqrt(3) = "
            << mag(refQ_) - sqrt(3.0) << nl
            << exit(FatalError);
    }
 
    sDoFRBMRCoeffs_.readEntry("stiffness", stiffness_);
    sDoFRBMRCoeffs_.readEntry("damping", damping_);
 
    return true;
}
 
 
void Foam::sixDoFRigidBodyMotionRestraints::sphericalAngularSpring::write
(
    Ostream& os
) const
{
    os.writeEntry("referenceOrientation", refQ_);
    os.writeEntry("stiffness", stiffness_);
    os.writeEntry("damping", damping_);
}
 
 
// ************************************************************************* //