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

   1 /*---------------------------------------------------------------------------*\
   2   =========                 |
   3   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   4    \\    /   O peration     |
   5     \\  /    A nd           | Copyright (C) 2010-2011 OpenCFD Ltd.
   6      \\/     M anipulation  |
   7 -------------------------------------------------------------------------------
   8 License
   9     This file is part of OpenFOAM.
  10
  11     OpenFOAM is free software: you can redistribute it and/or modify it
  12     under the terms of the GNU General Public License as published by
  13     the Free Software Foundation, either version 3 of the License, or
  14     (at your option) any later version.
  15
  16     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
  17     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  19     for more details.
  20
  21     You should have received a copy of the GNU General Public License
  22     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 \*---------------------------------------------------------------------------*/
  25
  26 #include "linearSpring.H"
  27 #include "addToRunTimeSelectionTable.H"
  28 #include "sixDoFRigidBodyMotion.H"
  29
  30 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
  31
  32 namespace Foam
  33 {
  34 namespace sixDoFRigidBodyMotionRestraints
  35 {
  36     defineTypeNameAndDebug(linearSpring, 0);
  37
  38     addToRunTimeSelectionTable
  39     (
  40         sixDoFRigidBodyMotionRestraint,
  41         linearSpring,
  42         dictionary
  43     );
  44 }
  45 }
  46
  47
  48 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
  49
  50 Foam::sixDoFRigidBodyMotionRestraints::linearSpring::linearSpring
  51 (
  52     const dictionary& sDoFRBMRDict
  53 )
  54 :
  55     sixDoFRigidBodyMotionRestraint(sDoFRBMRDict),
  56     anchor_(),
  57     refAttachmentPt_(),
  58     stiffness_(),
  59     damping_(),
  60     restLength_()
  61 {
  62     read(sDoFRBMRDict);
  63 }
  64
  65
  66 // * * * * * * * * * * * * * * * * Destructors * * * * * * * * * * * * * * * //
  67
  68 Foam::sixDoFRigidBodyMotionRestraints::linearSpring::~linearSpring()
  69 {}
  70
  71
  72 // * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
  73
  74 void Foam::sixDoFRigidBodyMotionRestraints::linearSpring::restrain
  75 (
  76     const sixDoFRigidBodyMotion& motion,
  77     vector& restraintPosition,
  78     vector& restraintForce,
  79     vector& restraintMoment
  80 ) const
  81 {
  82     restraintPosition = motion.currentPosition(refAttachmentPt_);
  83
  84     vector r = restraintPosition - anchor_;
  85
  86     scalar magR = mag(r);
  87
  88     // r is now the r unit vector
  89     r /= (magR + VSMALL);
  90
  91     vector v = motion.currentVelocity(restraintPosition);
  92
  93     restraintForce = -stiffness_*(magR - restLength_)*r - damping_*(r & v)*r;
  94
  95     restraintMoment = vector::zero;
  96
  97     if (motion.report())
  98     {
  99         Info<< " attachmentPt - anchor " << r*magR
 100             << " spring length " << magR
 101             << " force " << restraintForce
 102             << " moment " << restraintMoment
 103             << endl;
 104     }
 105 }
 106
 107
 108 bool Foam::sixDoFRigidBodyMotionRestraints::linearSpring::read
 109 (
 110     const dictionary& sDoFRBMRDict
 111 )
 112 {
 113     sixDoFRigidBodyMotionRestraint::read(sDoFRBMRDict);
 114
 115     sDoFRBMRCoeffs_.lookup("anchor") >> anchor_;
 116
 117     sDoFRBMRCoeffs_.lookup("refAttachmentPt") >> refAttachmentPt_;
 118
 119     sDoFRBMRCoeffs_.lookup("stiffness") >> stiffness_;
 120
 121     sDoFRBMRCoeffs_.lookup("damping") >> damping_;
 122
 123     sDoFRBMRCoeffs_.lookup("restLength") >> restLength_;
 124
 125     return true;
 126 }
 127
 128
 129 void Foam::sixDoFRigidBodyMotionRestraints::linearSpring::write
 130 (
 131     Ostream& os
 132 ) const
 133 {
 134     os.writeKeyword("anchor")
 135         << anchor_ << token::END_STATEMENT << nl;
 136
 137     os.writeKeyword("refAttachmentPt")
 138         << refAttachmentPt_ << token::END_STATEMENT << nl;
 139
 140     os.writeKeyword("stiffness")
 141         << stiffness_ << token::END_STATEMENT << nl;
 142
 143     os.writeKeyword("damping")
 144         << damping_ << token::END_STATEMENT << nl;
 145
 146     os.writeKeyword("restLength")
 147         << restLength_ << token::END_STATEMENT << nl;
 148 }
 149
 150 // ************************************************************************* //