问题：
圆柱绕流问题，模拟仿真有两个圆柱、一个源的流体变化情况。
解决步骤：
1.使用Gmsh画出网格，并保存cylindertwo.msh
2.以Cavity为基础创建新的Case：Cylindertwo,先将0，constant，system三个文件夹复制进Cylindertwo，将constant文件夹中的transportProperties文件复制出来，删除constant文件夹。
3.由于采用源码安装，使用以下代码启动OpenFoam.
source ~/OpenFOAM/OpenFOAM-v3.0+/etc/bashrc run
运行以下代码生成网格:
gmshToFoam
4.改写P，U和boundary文件,具体如何改写参见代码.
5.生产网格，进行计算，命令如下：
checkMesh renumberMesh -overwrite icoFoam
6.使用paraFoam命令查看效果.
paraFoam
画网格：
画出的网格效果如下：
Fg.1 mesh前三维图
Fg.2 mesh后三维图
代码：
cylindertwo.geo
// Gmsh project created on Wed Jun 29 11:30:24 2016
Nx = 41;Rx = 1.00;
Ny = 41;Ry = 1.00;
Nb = 41;Rb = 1.00;
Nc = 41;Rc = 1.00;
Point(1) = {-10,-10,0,1.0};
Point(2) = {10,-10,0,1.0};
Point(3) = {40,-10,0,1.0};
Point(4) = {-10,10,0,1.0};
Point(5) = {10,10,0,1.0};
Point(6) = {40,10,0,1.0};
//cylinder1 points
Point(7) = {-0.35355339,-0.35355339,0,1.0};
Point(8) = {0.35355339,-0.35355339,0,1.0};
Point(9) = {-0.35355339,0.35355339,0,1.0};
Point(10) = {0.35355339,0.35355339,0,1.0};
Point(11) = {0,0,0,1.0};
//cylinder2 points
Point(12) = {-0.35355339+30,-0.35355339,0,1.0};
Point(13) = {0.35355339+30,-0.35355339,0,1.0};
Point(14) = {-0.35355339+30,0.35355339,0,1.0};
Point(15) = {0.35355339+30,0.35355339,0,1.0};
Point(16) = {0+30,0,0,1.0};
Point(17) = {20,10,0,1.0};
Point(18) = {20,-10,0,1.0};
//x lines
Line(1) = {4, 5};Transfinite Line {1} = Nx Using Progression Rx;
Line(2) = {5, 17};Transfinite Line {2} = Nx Using Progression Rx;
Line(3) = {17, 6};Transfinite Line {3} = Nx Using Progression Rx;
Line(4) = {1, 2};Transfinite Line {4} = Nx Using Progression Rx;
Line(5) = {2, 18};Transfinite Line {5} = Nx Using Progression Rx;
Line(6) = {18, 3};Transfinite Line {6} = Nx Using Progression Rx;
//y lines
Line(7) = {4, 1};Transfinite Line {7} = Ny Using Bump Ry;
Line(8) = {5, 2};Transfinite Line {8} = Ny Using Bump Ry;
Line(9) = {17, 18};Transfinite Line {9} = Ny Using Bump Ry;
Line(10) = {6, 3};Transfinite Line {10} = Ny Using Bump Ry;
//cicle lines of one
Circle(11) = {9, 11, 10};Transfinite Line {11} = Nc Using Progression Rc;
Circle(12) = {10, 11, 8};Transfinite Line {12} = Nc Using Progression Rc;
Circle(13) = {8, 11, 7};Transfinite Line {13} = Nc Using Progression Rc;
Circle(14) = {7, 11, 9};Transfinite Line {14} = Nc Using Progression Rc;
//cicle lines of two
Circle(15) = {14, 16, 15};Transfinite Line {15} = Nc Using Progression Rc;
Circle(16) = {15, 16, 13};Transfinite Line {16} = Nc Using Progression Rc;
Circle(17) = {13, 16, 12};Transfinite Line {17} = Nc Using Progression Rc;
Circle(18) = {12, 16, 14};Transfinite Line {18} = Nc Using Progression Rc;
//block lines
Line(19) = {4, 9};Transfinite Line {19} = Nb Using Progression Rb;
Line(20) = {5, 10};Transfinite Line {20} = Nb Using Progression Rb;
Line(21) = {2, 8};Transfinite Line {21} = Nb Using Progression Rb;
Line(22) = {1, 7};Transfinite Line {22} = Nb Using Progression Rb;
Line(23) = {17, 14};Transfinite Line {23} = Nb Using Progression Rb;
Line(24) = {6, 15};Transfinite Line {24} = Nb Using Progression Rb;
Line(25) = {3, 13};Transfinite Line {25} = Nb Using Progression Rb;
Line(26) = {18, 12};Transfinite Line {26} = Nb Using Progression Rb;
//surfaces
Line Loop(27) = {1, 20, -11, -19};
Plane Surface(28) = {27};
Line Loop(29) = {7, 22, 14, -19};
Plane Surface(30) = {29};
Line Loop(31) = {4, 21, 13, -22};
Plane Surface(32) = {31};
Line Loop(33) = {8, 21, -12, -20};
Plane Surface(34) = {33};
Line Loop(35) = {2, 9, -5, -8};
Plane Surface(36) = {35};
Line Loop(37) = {3, 24, -15, -23};
Plane Surface(38) = {37};
Line Loop(39) = {9, 26, 18, -23};
Plane Surface(40) = {39};
Line Loop(41) = {6, 25, 17, -26};
Plane Surface(42) = {41};
Line Loop(43) = {10, 25, -16, -24};
Plane Surface(44) = {43};
Transfinite Surface {28};
Transfinite Surface {30};
Transfinite Surface {32};
Transfinite Surface {34};
Transfinite Surface {36};
Transfinite Surface {38};
Transfinite Surface {40};
Transfinite Surface {42};
Transfinite Surface {44};
Recombine Surface {28};
Recombine Surface {30};
Recombine Surface {32};
Recombine Surface {34};
Recombine Surface {36};
Recombine Surface {38};
Recombine Surface {40};
Recombine Surface {42};
Recombine Surface {44};
Extrude {0, 0, 2} {
Surface{28, 30, 32, 34, 36, 40, 38, 44, 42};
Layers{1};
Recombine;
}
Physical Surface("inlet") = {75};//inlet
Physical Surface("outlet") = {207};//outlet
Physical Surface("top") = {53, 141, 185};//top
Physical Surface("bottom") = {97, 149, 229};//bottom
Physical Surface("cylinderWalls_1") = {61, 83, 105, 127};//cylinderWalls_1
Physical Surface("cylinderWalls_2") = {193, 171, 237, 215};//cylinderWalls_2
Physical Surface("frontAndBack") = {66, 88, 110, 132, 154, 176, 198, 220, 242, 30, 32, 28, 34, 36, 40, 42, 44, 38};
//frontAndBack
Physical Volume("internal") = {1,2,3,4,5,6,7,8,9};//internal
P
/*--------------------------------*- C++ -*----------------------------------*
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: v3.0+ |
| \ / A nd | Web: www.OpenFOAM.com |
| \/ M anipulation | |
*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
frontAndBack
{
type empty;
}
top
{
type zeroGradient;
}
cylinderWalls_1
{
type zeroGradient;
}
inlet
{
type zeroGradient;
}
bottom
{
type zeroGradient;
}
cylinderWalls_2
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
}
// ************************************************************************* //
U
/*--------------------------------*- C++ -*----------------------------------*
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: v3.0+ |
| \ / A nd | Web: www.OpenFOAM.com |
| \/ M anipulation | |
*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
location "0";
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
frontAndBack
{
type empty;
}
top
{
type slip;
}
cylinderWalls_1
{
type fixedValue;
value uniform (0 0 0);
}
inlet
{
type fixedValue;
value uniform (1 0 0);
}
bottom
{
type slip;
}
cylinderWalls_2
{
type fixedValue;
value uniform (0 0 0);
}
outlet
{
type zeroGradient;
}
}
// ************************************************************************* //
Boundary
/*--------------------------------*- C++ -*----------------------------------*
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: v3.0+ |
| \ / A nd | Web: www.OpenFOAM.com |
| \/ M anipulation | |
*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class polyBoundaryMesh;
location "constant/polyMesh";
object boundary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
7
(
frontAndBack
{
type empty;
inGroups 1(empty);
nFaces 28800;
startFace 28480;
}
top
{
type patch;
physicalType patch;
nFaces 120;
startFace 57280;
}
cylinderWalls_1
{
type patch;
physicalType patch;
nFaces 160;
startFace 57400;
}
inlet
{
type patch;
physicalType patch;
nFaces 40;
startFace 57560;
}
bottom
{
type patch;
physicalType patch;
nFaces 120;
startFace 57600;
}
cylinderWalls_2
{
type patch;
physicalType patch;
nFaces 160;
startFace 57720;
}
outlet
{
type patch;
physicalType patch;
nFaces 40;
startFace 57880;
}
)
// ************************************************************************* //
controlDict
/*--------------------------------*- C++ -*----------------------------------*
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: v3.0+ |
| \ / A nd | Web: www.OpenFOAM.com |
| \/ M anipulation | |
*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
application icoFoam;
startFrom startTime;
startTime 0;
stopAt endTime;
endTime 100;
deltaT 0.005;
writeControl timeStep;
writeInterval 20;
purgeWrite 0;
writeFormat ascii;
writePrecision 6;
writeCompression off;
timeFormat general;
timePrecision 6;
runTimeModifiable true;
// ************************************************************************* //
结果展示：
Fg3 T = 0
Fg4 T = 40
Fg8 T = 200
Fg11 T = 600
Fg13 T = 725