OpenFOAM&Gmsh&CFD圆柱绕流（两个圆柱）

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