src/lagrangian/molecularDynamics/potential/tetherPotential/derived/restrainedHarmonicSpring/restrainedHarmonicSpring.C

   1 /*---------------------------------------------------------------------------*\
   2   =========                 |
   3   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   4    \\    /   O peration     |
   5     \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
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   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 "restrainedHarmonicSpring.H"
  27 #include "addToRunTimeSelectionTable.H"
  28
  29 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
  30
  31 namespace Foam
  32 {
  33 namespace tetherPotentials
  34 {
  35
  36 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
  37
  38 defineTypeNameAndDebug(restrainedHarmonicSpring, 0);
  39
  40 addToRunTimeSelectionTable
  41 (
  42     tetherPotential,
  43     restrainedHarmonicSpring,
  44     dictionary
  45 );
  46
  47
  48 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
  49
  50 restrainedHarmonicSpring::restrainedHarmonicSpring
  51 (
  52     const word& name,
  53     const dictionary& tetherPotentialProperties
  54 )
  55 :
  56     tetherPotential(name, tetherPotentialProperties),
  57     restrainedHarmonicSpringCoeffs_
  58     (
  59         tetherPotentialProperties.subDict(typeName + "Coeffs")
  60     ),
  61     springConstant_
  62     (
  63         readScalar(restrainedHarmonicSpringCoeffs_.lookup("springConstant"))
  64     ),
  65     rR_
  66     (
  67         readScalar(restrainedHarmonicSpringCoeffs_.lookup("rR"))
  68     )
  69 {}
  70
  71 // * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
  72
  73 scalar restrainedHarmonicSpring::energy(const vector r) const
  74 {
  75     scalar magR = mag(r);
  76
  77     if (magR < rR_)
  78     {
  79         return 0.5 * springConstant_ * magSqr(r);
  80     }
  81     else
  82     {
  83         return 0.5 * springConstant_ * rR_ * rR_
  84           + springConstant_ * rR_ * (magR - rR_);
  85     }
  86 }
  87
  88
  89 vector restrainedHarmonicSpring::force(const vector r) const
  90 {
  91     scalar magR = mag(r);
  92
  93     if (magR < rR_)
  94     {
  95         return -springConstant_ * r;
  96     }
  97     else
  98     {
  99         return -springConstant_ * rR_ * r / magR;
 100     }
 101 }
 102
 103
 104 bool restrainedHarmonicSpring::read
 105 (
 106     const dictionary& tetherPotentialProperties
 107 )
 108 {
 109     tetherPotential::read(tetherPotentialProperties);
 110
 111     restrainedHarmonicSpringCoeffs_ =
 112         tetherPotentialProperties.subDict(typeName + "Coeffs");
 113
 114     restrainedHarmonicSpringCoeffs_.lookup("springConstant") >> springConstant_;
 115     restrainedHarmonicSpringCoeffs_.lookup("rR") >> rR_;
 116
 117     return true;
 118 }
 119
 120
 121 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 122
 123 } // End namespace tetherPotentials
 124 } // End namespace Foam
 125
 126 // ************************************************************************* //