FreeFOAM The Cross-Platform CFD Toolkit
basicXiSubXiEq.H
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23 
24 Class
25  Foam::XiEqModels::basicSubGrid
26 
27 Description
28  Basic sub-grid obstacle flame-wrinking enhancement factor model.
29  Details supplied by J Puttock 2/7/06.
30 
31  <b> Sub-grid flame area generation </b>
32 
33  \f$ n = N - \hat{\dwea{\vec{U}}}.n_{s}.\hat{\dwea{\vec{U}}} \f$
34  \f$ n_{r} = \sqrt{n} \f$
35 
36  where:
37 
38  \f$ \hat{\dwea{\vec{U}}} = \dwea{\vec{U}} / \vert \dwea{\vec{U}}
39  \vert \f$
40 
41  \f$ b = \hat{\dwea{\vec{U}}}.B.\hat{\dwea{\vec{U}}} / n_{r} \f$
42 
43  where:
44 
45  \f$ B \f$ is the file "B".
46 
47  \f$ N \f$ is the file "N".
48 
49  \f$ n_{s} \f$ is the file "ns".
50 
51  The flame area enhancement factor \f$ \Xi_{sub} \f$ is expected to
52  approach:
53 
54  \f[
55  \Xi_{{sub}_{eq}} =
56  1 + max(2.2 \sqrt{b}, min(0.34 \frac{\vert \dwea{\vec{U}}
57  \vert}{{\vec{U}}^{'}}, 1.6)) \times min(\frac{n}{4}, 1)
58  \f]
59 
60 
61 SourceFiles
62  basicSubGrid.C
63 
64 \*---------------------------------------------------------------------------*/
65 
66 #ifndef basicSubGrid_H
67 #define basicSubGrid_H
68 
70 
71 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
72 
73 namespace Foam
74 {
75 namespace XiEqModels
76 {
77 
78 /*---------------------------------------------------------------------------*\
79  Class basicSubGrid Declaration
80 \*---------------------------------------------------------------------------*/
81 
83 :
84  public XiEqModel
85 {
86  // Private data
87 
88  //- Count
89  volScalarField N_;
90 
91  //- Sub-count
93 
94  //- tblock
96 
97  //- Typical obstacle diameters per cell
98  volScalarField Lobs_;
99 
100  //- Equilibrium Xi model due to turbulence
101  autoPtr<XiEqModel> XiEqModel_;
102 
103 
104  // Private Member Functions
105 
106  //- Disallow copy construct
107  basicSubGrid(const basicSubGrid&);
108 
109  //- Disallow default bitwise assignment
110  void operator=(const basicSubGrid&);
111 
112 
113 public:
114 
115  //- Runtime type information
116  TypeName("basicSubGrid");
117 
118 
119  // Constructors
120 
121  //- Construct from components
123  (
124  const dictionary& XiEqProperties,
127  const volScalarField& Su
128  );
129 
130 
131  // Destructor
132 
133  virtual ~basicSubGrid();
134 
135 
136  // Member Functions
137 
138  //- Return the flame-wrinking XiEq
139  virtual tmp<volScalarField> XiEq() const;
140 
141  //- Update properties from given dictionary
142  virtual bool read(const dictionary& XiEqProperties);
143 };
144 
145 
146 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
147 
148 } // End namespace XiEqModels
149 } // End namespace Foam
150 
151 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
152 
153 #endif
154 
155 // ************************ vim: set sw=4 sts=4 et: ************************ //