1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
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.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
Class
Foam::PDRDragModels::basic
Description
Basic sub-grid obstacle drag model.
Details supplied by J Puttock 2/7/06.
<b> Sub-grid drag term </b>
The resistance term (force per unit of volume) is given by:
\f[
R = -\frac{1}{2} \rho \vert \dwea{\vec{U}} \vert \dwea{\vec{U}}.D
\f]
where:
\f$ D \f$ is the tensor field "CR" in \f$ m^{-1} \f$
This is term is treated implicitly in UEqn.H
<b> Sub-grid turbulence generation </b>
The turbulence source term \f$ G_{R} \f$ occurring in the
\f$ \kappa-\epsilon \f$ equations for the generation of turbulence due
to interaction with unresolved obstacles :
\f$ G_{R} = C_{s}\beta_{\nu}
\mu_{eff} A_{w}^{2}(\dwea{\vec{U}}-\dwea{\vec{U}_{s}})^2 + \frac{1}{2}
\rho \vert \dwea{\vec{U}} \vert \dwea{\vec{U}}.T.\dwea{\vec{U}} \f$
where:
\f$ C_{s} \f$ = 1
\f$ \beta_{\nu} \f$ is the volume porosity (file "betav").
\f$ \mu_{eff} \f$ is the effective viscosity.
\f$ A_{w}^{2}\f$ is the obstacle surface area per unit of volume
(file "Aw").
\f$ \dwea{\vec{U}_{s}} \f$ is the slip velocity and is considered
\f$ \frac{1}{2}. \dwea{\vec{U}} \f$.
\f$ T \f$ is a tensor in the file CT.
The term \f$ G_{R} \f$ is treated explicitly in the \f$ \kappa-\epsilon
\f$ Eqs in the \link PDRkEpsilon.C \endlink file.
SourceFiles
basic.C
\*---------------------------------------------------------------------------*/
#ifndef basic_H
#define basic_H
#include "PDRDragModel.H"
#include "XiEqModel.H"
namespace Foam
{
namespace PDRDragModels
{
/*---------------------------------------------------------------------------*\
Class basic Declaration
\*---------------------------------------------------------------------------*/
class basic
:
public PDRDragModel
{
// Private data
dimensionedScalar Csu;
dimensionedScalar Csk;
volScalarField Aw_;
volSymmTensorField CR_;
// Private Member Functions
//- Disallow copy construct
basic(const basic&);
//- Disallow default bitwise assignment
void operator=(const basic&);
public:
//- Runtime type information
TypeName("basic");
// Constructors
//- Construct from components
basic
(
const dictionary& PDRProperties,
const compressible::RASModel& turbulence,
const volScalarField& rho,
const volVectorField& U,
const surfaceScalarField& phi
);
//- Destructor
virtual ~basic();
// Member Functions
//- Return the momentum drag coefficient
virtual tmp<volSymmTensorField> Dcu() const;
//- Return the momentum drag turbulence generation rate
virtual tmp<volScalarField> Gk() const;
//- Update properties from given dictionary
virtual bool read(const dictionary& PDRProperties);
//- Write fields
void writeFields() const;
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace PDRDragModels
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //
|
