[jwh107]

Hello.
Recently I am doing some ducted fan simulation with openFoam.
I faced bad errors. (Wedge Planner error)
But it is now cleared and I can actually run the case.
But I see the result is completely wrong compare to what I want to simulate.

right.png

right_p.png

I want this kind of simulation result. But I got a strange result.

Like this

wrong_v.png

wrong_p.png

I created a axis symmetry ducted fan geometry and meshing it with Gmsh 12.0.2. Also, I created baffle in the ducted fan so that I can simulate a propeller with pressure jump.

It seems the pressure was jumped but the velocity is not changed at all.
I don't know why
could you shed some light on this case?

In case of you are asking how I set the baffledict or other things.
It goes same with this youtube. The only difference is mesh.

https://www.youtube.com/watch?v=qTYAr8jgViM

My mesh is looks like this

https://drive.google.com/file/d/0B2L...ew?usp=sharing

https://drive.google.com/file/d/0B2L...ew?usp=sharing

https://drive.google.com/file/d/0B2L...ew?usp=sharing

Mesh file (with gmsh)

Point(1) = {	326.8521	,	-47.7156	,	0	};
Point(2) = {	326.1980	,	-32.7490	,	0	};
Point(3) = {	322.3840	,	-19.0429	,	0	};
Point(4) = {	315.8702	,	-8.2505	,	0	};
Point(5) = {	307.4422	,	-1.6735	,	0	};
Point(6) = {	297.8010	,	-0.0336	,	0	};
Point(7) = {	286.8294	,	-1.2079	,	0	};
Point(8) = {	275.9581	,	-4.0512	,	0	};
Point(9) = {	265.2697	,	-8.5418	,	0	};
Point(10) = {	254.8456	,	-14.6455	,	0	};
Point(11) = {	244.7652	,	-22.3159	,	0	};
Point(12) = {	235.1052	,	-31.4946	,	0	};
Point(13) = {	225.9391	,	-42.1118	,	0	};
Point(14) = {	217.3366	,	-54.0865	,	0	};
Point(15) = {	209.3632	,	-67.3278	,	0	};
Point(16) = {	202.0796	,	-81.7349	,	0	};
Point(17) = {	195.5413	,	-97.1980	,	0	};
Point(18) = {	189.7979	,	-113.5995	,	0	};
Point(19) = {	184.8933	,	-130.8146	,	0	};
Point(20) = {	180.8647	,	-148.7122	,	0	};
Point(21) = {	177.7427	,	-167.1562	,	0	};
Point(22) = {	175.5513	,	-186.0062	,	0	};
Point(23) = {	174.3069	,	-205.1187	,	0	};
Point(24) = {	174.0192	,	-224.3483	,	0	};
Point(25) = {	174.6902	,	-243.5485	,	0	};
Point(26) = {	179.6902	,	-260.0080	,	0	};
Point(27) = {	184.6902	,	-276.4675	,	0	};
Point(28) = {	189.6902	,	-292.9269	,	0	};
Point(29) = {	194.6902	,	-309.3864	,	0	};
Point(30) = {	199.6902	,	-325.8459	,	0	};
Point(31) = {	204.6902	,	-342.3053	,	0	};
Point(32) = {	209.6902	,	-358.7648	,	0	};
Point(33) = {	214.6902	,	-375.2243	,	0	};
Point(34) = {	219.6902	,	-391.6838	,	0	};
Point(35) = {	224.6902	,	-408.1432	,	0	};
Point(36) = {	229.6902	,	-424.6027	,	0	};
Point(37) = {	234.6902	,	-441.0622	,	0	};
Point(38) = {	239.6902	,	-419.7222	,	0	};
Point(39) = {	244.6902	,	-398.3822	,	0	};
Point(40) = {	249.6902	,	-377.0422	,	0	};
Point(41) = {	254.6902	,	-355.7022	,	0	};
Point(42) = {	259.6902	,	-334.3622	,	0	};
Point(43) = {	264.6902	,	-313.0222	,	0	};
Point(44) = {	269.6902	,	-291.6823	,	0	};
Point(45) = {	274.6902	,	-270.3423	,	0	};
Point(46) = {	279.6902	,	-249.0023	,	0	};
Point(47) = {	284.6902	,	-227.6623	,	0	};
Point(48) = {	289.6902	,	-206.3223	,	0	};
Point(49) = {	294.6902	,	-184.9823	,	0	};
Point(50) = {	299.6902	,	-163.6423	,	0	};
Point(51) = {	304.6902	,	-142.3023	,	0	};
Point(52) = {	309.6902	,	-120.9624	,	0	};
Point(53) = {	314.6902	,	-99.6224	,	0	};
Point(54) = {	319.6902	,	-78.2824	,	0	};
Point(55) = {	324.6902	,	-56.9424	,	0	};

Line(56) = {1:55,1};

Line Loop(57) = {56};

Point(58) = {0, -2000, 0, 100};
Point(59) = {0, 1500, 0, 100};
Point(60) = {2000, 1500, 0, 100};
Point(61) = {2000, -2000, 0, 100};
Point(62) = {0, -243.5, 0, 100};

Line(63) = {25, 62};
Line(64) = {62, 59};
Line(65) = {59, 60};
Line(66) = {60, 61};
Line(67) = {61, 58};
Line(68) = {58, 62};
Line(69) = {62, 25};

Line Loop(70) = {63:69};

Plane Surface(71) = {57, 70};


Transfinite Line {64, 68} = 200 Using Progression 1;
Transfinite Line {67, 65} = 100 Using Progression 1;
Transfinite Line {66} = 30 Using Progression 1;
Transfinite Line {63} = 60 Using Progression 1;
Transfinite Line {56} = 2000 Using Progression 1;

Rotate {{0,1,0},{0,0,0},2.5*Pi/180.0}
{
	Surface{71};
}
new_entities[] = Extrude {{0,1,0},{0,0,0},-5*Pi/180.0}
{
	Surface{71};
	Layers{1};
	Recombine;
};

Physical Surface("wedge0") = {71};
Physical Surface("wedge1") = {new_entities[0]};
Physical Surface("outlet") = {new_entities[4]};
Physical Surface("tunnel") = {new_entities[5]};
Physical Surface("inlet") = {new_entities[6]};
Physical Surface("duct") = {new_entities[2]};
Physical Surface("baffle") = {new_entities[7]}; // or 3

Physical Volume("AIR") = {1};

CheckMesh result

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.0                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 4.0-665f1db4c1f1
Exec   : checkMesh
Date   : Aug 13 2016
Time   : 23:22:44
Host   : "hyeon-System-Product-Name"
PID    : 7356
Case   : /home/hyeon/DuctedFan3/case
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
    points:           146363
    internal points:  0
    faces:            505455
    internal faces:   214837
    cells:            144138
    faces per cell:   4.99724
    boundary patches: 8
    point zones:      0
    face zones:       2
    cell zones:       1

Overall number of cells of each type:
    hexahedra:     0
    prisms:        143288
    wedges:        0
    pyramids:      452
    tet wedges:    0
    tetrahedra:    398
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces...
    Patch               Faces    Points   Surface topology                  
    wedge0              144138   73381    ok (non-closed singly connected)  
    baffle              58       117      ok (non-closed singly connected)  
    baffleother         58       117      ok (non-closed singly connected)  
    outlet              99       199      ok (non-closed singly connected)  
    inlet               99       199      ok (non-closed singly connected)  
    wedge1              144138   73381    ok (non-closed singly connected)  
    duct                1999     3998     ok (non-closed singly connected)  
    tunnel              29       60       ok (non-closed singly connected)  

Checking geometry...
    Overall domain bounding box (0 -2000 -87.2388) (1998.1 1500 87.2388)
    Mesh has 2 geometric (non-empty/wedge) directions (1 1 0)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Wedge wedge0 with angle 2.5 degrees
    Wedge wedge1 with angle 2.5 degrees
    All edges aligned with or perpendicular to non-empty directions.
    Boundary openness (5.76858e-16 -5.3271e-18 1.47418e-16) OK.
    Max cell openness = 3.26385e-16 OK.
    Max aspect ratio = 20.3504 OK.
    Minimum face area = 0.000547878. Maximum face area = 26007.7.  Face area magnitudes OK.
    Min volume = 0.00834115. Max volume = 1.25855e+06.  Total volume = 6.09302e+08.  Cell volumes OK.
    Mesh non-orthogonality Max: 71.881 average: 7.42978
   *Number of severely non-orthogonal (> 70 degrees) faces: 2.
    Non-orthogonality check OK.
  <<Writing 2 non-orthogonal faces to set nonOrthoFaces
    Face pyramids OK.
    Max skewness = 1.19735 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

End

Createbaffles result

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.0                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 4.0-665f1db4c1f1
Exec   : createBaffles -case case -dict system/baffleDict -overwrite
Date   : Aug 13 2016
Time   : 23:22:11
Host   : "hyeon-System-Product-Name"
PID    : 7344
Case   : ./case
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

Reading baffle criteria from createBafflesDict

Not converting faces on non-coupled patches.

Reading geometric fields

Reading volScalarField p
Reading volScalarField nuTilda
Reading volScalarField nut
Reading volVectorField U
Created zone baffleFaces at index 1 with 58 faces
Patch 'baffle' already exists.  Only moving patch faces - type will remain the same
Patch 'baffleother' already exists.  Only moving patch faces - type will remain the same
Converted 58 faces into boundary faces in patches 
2
(
baffle
baffleother
)


--> FOAM Warning : 
    From function int main(int, char**)
    in file createBaffles.C at line 843
    Setting field on boundary faces to zero.
You might have to edit these fields.
Writing mesh to 0
End

GmeshToFoam result

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.0                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 4.0-665f1db4c1f1
Exec   : gmshToFoam test.msh -case case
Date   : Aug 13 2016
Time   : 23:19:56
Host   : "hyeon-System-Product-Name"
PID    : 7325
Case   : ./case
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Starting to read mesh format at line 2
Read format version 2.2  ascii 0

Starting to read physical names at line 5
Physical names:8
    Surface 1	wedge0
    Surface 2	wedge1
    Surface 3	outlet
    Surface 4	tunnel
    Surface 5	inlet
    Surface 6	duct
    Surface 7	baffle
    Volume 8	AIR

Starting to read points at line 16
Vertices to be read:146363
Vertices read:146363

Starting to read cells at line 146382
Cells to be read:434699

Mapping region 1 to Foam patch 0
Mapping region 7 to Foam patch 1
Mapping region 3 to Foam patch 2
Mapping region 5 to Foam patch 3
Mapping region 2 to Foam patch 4
Mapping region 6 to Foam patch 5
Mapping region 4 to Foam patch 6
Mapping region 8 to Foam cellZone 0
Cells:
    total:144138
    hex  :0
    prism:143288
    pyr  :452
    tet  :398

CellZones:
Zone	Size
    0	144138

Skipping tag  at line 581084
Patch 0 gets name wedge0
Patch 1 gets name baffle
Patch 2 gets name outlet
Patch 3 gets name inlet
Patch 4 gets name wedge1
Patch 5 gets name duct
Patch 6 gets name tunnel

--> FOAM Warning : 
    From function Foam::polyMesh::polyMesh(const Foam::IOobject&, const Foam::Xfer<Foam::Field<Foam::Vector<double> > >&, const cellShapeList&, const faceListList&, const wordList&, const wordList&, const Foam::word&, const Foam::word&, const wordList&, bool)
    in file meshes/polyMesh/polyMeshFromShapeMesh.C at line 595
    Found 290502 undefined faces in mesh; adding to default patch.
Finding faces of patch 0
Finding faces of patch 1
--> FOAM Warning : 
    From function int main(int, char**)
    in file gmshToFoam.C at line 972
    Could not match gmsh face 4(1 2009 4685 8) to any of the interior or exterior faces that share the same 0th point
Finding faces of patch 2
Finding faces of patch 3
Finding faces of patch 4
Finding faces of patch 5
Finding faces of patch 6

FaceZones:
Zone	Size
    1	58

Writing zone 0 to cellZone AIR and cellSet
Writing zone 1 to faceZone baffle and faceSet
End

[tareqkh]

Hi Woo,

If you still have the issue, please reply back since I have done similar simulation before and think that I can help.

Best,

[jiahui_93]

Originally Posted by tareqkh

Hi Woo,

If you still have the issue, please reply back since I have done similar simulation before and think that I can help.

Best,

Hi, i am now facing the same problem, which the internal boundary is not recognized, so the flow passed through without any blocking effect as shown in the picture posted above. May I get some suggestion on how to solve this. Thanks a lot for help =)

[piu58]

> internal boundary is not recognized, so the flow passed through without any blocking effect

Boundaries are one sided in OpenFoam. If you don't mention that, flow is only blocked in one direction.

[jiahui_93]

Originally Posted by piu58

> internal boundary is not recognized, so the flow passed through without any blocking effect

Boundaries are one sided in OpenFoam. If you don't mention that, flow is only blocked in one direction.

Hi, thanks for reply. My case is worse that the flow doesn't get blocked in any direction. Even i created baffle, but with output 0 faces converted into boundary faces in patches. May i get some suggestion on how to solve this? I was struggling this for months n tried many type of meshing method. Yet still cannot be solved. thanks

[piu58]

I did not analyse you case en détail. But I assume that is save to implement a double boundary, enclosing a small amount of empty space.

[jiahui_93]

Originally Posted by piu58

I did not analyse you case en détail. But I assume that is save to implement a double boundary, enclosing a small amount of empty space.

Thanks for your suggestion. I will try it. Is the double boundary you mentioned are baffle master and baffle slave?

[piu58]

> baffle master and baffle slave

I don't know these terms. I mean something like this:

[jiahui_93]

Originally Posted by piu58

> baffle master and baffle slave

I don't know these terms. I mean something like this:

thanks a lot for reply. If i would like to make a baffle box, i need to do double layer instead of 1 layer. Please correct me if I misunderstood your meaning.double baffle.jpg

Since every baffle consists of master and slave, I would like to ask, do anyone know, is the baffle1 is baffle_master while baffle2 is baffle_slave?
or baffle1 has own master and slave (baffle1_master and baffle1_slave) and so do baffle2 (baffle2_master and baffle2_slave)?

Thanks again =)

[piu58]

I only recommend a "double layer" if both sides are meshed (material). To circumvent an empty are you don't need two layers. But keep in mind, that you give the nodes of the patches in the right order. Otherwise you changed inside and outside and get very strange results.

[jiahui_93]

Originally Posted by piu58

I only recommend a "double layer" if both sides are meshed (material). To circumvent an empty are you don't need two layers. But keep in mind, that you give the nodes of the patches in the right order. Otherwise you changed inside and outside and get very strange results.

Thanks a lot for your help =)