FreeFOAM The Cross-Platform CFD Toolkit
pitchForkRing.C
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1 /*---------------------------------------------------------------------------*\
2  ========= |
3  \\ / F ield | OpenFOAM: The Open Source CFD Toolbox
4  \\ / O peration |
5  \\ / A nd | Copyright (C) 2008-2010 OpenCFD Ltd.
6  \\/ M anipulation |
7 -------------------------------------------------------------------------------
8 License
9  This file is part of OpenFOAM.
10 
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19  for more details.
20 
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22  along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
23 
24 \*---------------------------------------------------------------------------*/
25 
26 #include "pitchForkRing.H"
28 
29 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
30 
31 namespace Foam
32 {
33 namespace tetherPotentials
34 {
35 
36 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
37 
38 defineTypeNameAndDebug(pitchForkRing, 0);
39 
41 (
42  tetherPotential,
43  pitchForkRing,
44  dictionary
45 );
46 
47 
48 // * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
49 
51 (
52  const word& name,
53  const dictionary& tetherPotentialProperties
54 )
55 :
56  tetherPotential(name, tetherPotentialProperties),
57  pitchForkRingCoeffs_
58  (
59  tetherPotentialProperties.subDict(typeName + "Coeffs")
60  ),
61  mu_(readScalar(pitchForkRingCoeffs_.lookup("mu"))),
62  alpha_(readScalar(pitchForkRingCoeffs_.lookup("alpha"))),
63  rOrbit_(readScalar(pitchForkRingCoeffs_.lookup("rOrbit")))
64 {}
65 
66 
67 // * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
68 
69 scalar pitchForkRing::energy(const vector r) const
70 {
71  scalar p = sqrt(r.x()*r.x() + r.y()*r.y());
72 
73  scalar pMinusRSqr = (p - rOrbit_)*(p - rOrbit_);
74 
75  return -0.5 * mu_ * pMinusRSqr
76  + 0.25 * pMinusRSqr * pMinusRSqr
77  + 0.5 * alpha_ * r.z() * r.z();
78 }
79 
80 
82 {
83  scalar p = sqrt(r.x()*r.x() + r.y()*r.y());
84 
85  scalar pMinusR = (p - rOrbit_);
86 
87  return vector
88  (
89  (mu_ - pMinusR * pMinusR) * pMinusR * r.x()/p,
90  (mu_ - pMinusR * pMinusR) * pMinusR * r.y()/p,
91  -alpha_ * r.z()
92  );
93 }
94 
95 
96 bool pitchForkRing::read(const dictionary& tetherPotentialProperties)
97 {
98  tetherPotential::read(tetherPotentialProperties);
99 
100  pitchForkRingCoeffs_ =
101  tetherPotentialProperties.subDict(typeName + "Coeffs");
102 
103  pitchForkRingCoeffs_.lookup("mu") >> mu_;
104  pitchForkRingCoeffs_.lookup("alpha") >> alpha_;
105  pitchForkRingCoeffs_.lookup("rOrbit") >> rOrbit_;
106 
107  return true;
108 }
109 
110 
111 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
112 
113 } // End namespace tetherPotentials
114 } // End namespace Foam
115 
116 // ************************ vim: set sw=4 sts=4 et: ************************ //