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Old   February 9, 2011, 00:39
Default block mesh wedge
  #1
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William
Join Date: Feb 2011
Location: Minnesota USA
Posts: 33
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Hey,
I'm having a hard time getting the wedge to look right. Can somebody tell me what I am doing wrong.

Quote:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.7.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
convertToMeters 0.146;

vertices
(
(0 241.3 0) //0
(0 0 0) //1
(0 -12.7 0) //2
(0 -1524 0) //3
(279.4 -12.7 0) //4
(279.4 0 0) //5
(292.1 38.1 0) //6
(292.1 -313.6926357352644 0) //7
(304.8 38.1 0) //8
(304.8 13.51505771044411 0) //9
(304.8 0 0) //10
(304.8 -304.8 0) //11
(863.6 216.9016246183983 0) //12
(863.6 -521.7016246183977 0) //13
(867.943655820235 204.9675283344171 0) //14
(867.943655820235 -509.767528334418 0) //15
(7620 241.3 0) //16
(7620 -1524 0) //17
(279.1341 -12.7 12.1873) //18
(279.1341 0 12.1873) //19
(291.822 38.1 12.7412) //20
(291.822 -313.6926357352644 12.7412) //21
(304.5099 38.1 13.2952) //22
(304.5099 13.51505771044411 13.952) //23
(304.5099 0 13.29522) //24
(304.5099 -304.8 13.2952) //25
(862.7780 216.9016246183983 37.6697) //26
(862.7780 -521.7016246183977 37.6697) //27
(867.1176 204.9675283344171 37.8592) //28
(867.1176 -509.767528334418 37.8592) //29
(7612.7474 241.3 332.3797) //30
(7612.7474 -1524 332.3797) //31
(279.1341 -12.7 -12.1873) //32
(279.1341 0 -12.1873) //33
(291.822 38.1 -12.7412) //34
(291.822 -313.6926357352644 -12.7412) //35
(304.5099 38.1 -13.2952) //36
(304.5099 13.51505771044411 -13.2952) //37
(304.5099 0 -13.2952) //38
(304.5099 -304.8 -13.2952) //39
(862.7780 216.9016246183983 -37.6697) //40
(862.7780 -521.7016246183977 -37.6697) //41
(867.1176 204.9675283344171 -37.8592) //42
(867.1176 -509.767528334418 -37.8592) //43
(7612.7474 241.3 -332.3797) //44
(7612.7474 -1524 -332.3797) //45
);

blocks
(
hex (3 31 45 3 0 30 44 0) (10 10 10) simpleGrading (1 1 1)
hex (2 18 32 2 1 19 33 1) (10 10 10) simpleGrading (1 1 1)
hex (21 25 39 35 20 22 36 34) (10 10 10) simpleGrading (1 1 1)
hex (27 41 35 21 29 43 39 25) (10 10 10) simpleGrading (1 1 1)
hex (38 42 40 37 24 28 26 23) (10 10 10) simpleGrading (1 1 1)
);

edges
(
arc 45 31 (0 -1524 0)
arc 44 30 (0 241.3 0)
arc 43 29 (0 -509.767528334418 0)
arc 42 28 (0 204.9675283344171 0)
arc 41 27 (0 -521.7016246183977 0)
arc 40 26 (0 216.9016246183983 0)
arc 39 25 (0 -304.8 0)
arc 38 24 (0 0 0)
arc 37 23 (0 13.51505771044411 0)
arc 36 22 (0 38.1 0)
arc 35 21 (0 -313.6926357352644 0)
arc 34 20 (0 38.1 0)
arc 33 19 (0 0 0)
arc 32 18 (0 -12.7 0)
);

patches
(
wall AER
(
(20 34 35 21)
(21 35 41 27)
(27 41 43 29)
(29 43 39 25)
(25 39 36 22)
(24 38 42 28)
(28 42 40 26)
(26 40 37 23)
(22 36 34 20)
)
wall Top
(
(0 30 44 0)
)
wall bottom
(
(3 45 31 3)
)
wall back
(
(31 45 44 30)
)
patch inlet
(
(2 32 18 2)
)
patch outlet
(
(1 19 33 1)
)
wall nub
(
(18 32 33 19)
)
wedge side1
(
(0 3 31 30)
(20 21 25 22)
(21 27 29 25)
(24 28 26 23)
(1 2 18 19)
)
wedge side2
(
(0 3 45 44)
(34 36 39 35)
(35 39 43 41)
(37 38 42 40)
(1 33 32 2)
)
/*symmetryPlane symmetrywall
(
(0 16 17 3)
(1 4 5 2)
(6 8 11 7)
(7 11 15 13)
(9 12 14 10)
) */
empty zoinks
(
(3 3 0 0)
(2 2 1 1)
)
);

mergePatchPairs
(

);
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Old   February 12, 2011, 07:25
Default
  #2
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Radko Bankras
Join Date: Jul 2010
Location: Almere, The Netherlands
Posts: 5
Rep Power: 7
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billynoe,

Your wedge looks better if you don't split up your blocks, so:
Code:
    hex (3 31 45 3 0 30 44 0) (1 1 1) simpleGrading (1 1 1)
    hex (2 18 32 2 1 19 33 1) (1 1 1) simpleGrading (1 1 1)
    hex (21 25 39 35 20 22 36 34) (1 1 1) simpleGrading (1 1 1)
    hex (27 41 35 21 29 43 39 25) (1 1 1) simpleGrading (1 1 1)
    hex (38 42 40 37 24 28 26 23) (1 1 1) simpleGrading (1 1 1)
This will result in one undefined internal face in your AER patch, and a mesh which makes more sense.

I guess the AER patch defines internal walls in the wedge of your cylinder. In that case I would define only the blocks which form the volume of your wedge together. This way it is easier to increase the grading in X and Y direction, and you can keep your wedge 1 cell thick.

Kind regards, Radko

Last edited by Radko; February 12, 2011 at 07:25. Reason: style
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Old   February 14, 2011, 12:08
Default
  #3
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William
Join Date: Feb 2011
Location: Minnesota USA
Posts: 33
Rep Power: 6
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Yes that definitely fixed the shape I changed the faces to (1 1 1) on the AER block and input output and (15 1 5) on the wedge. I am getting errors in checkMesh from the internal walls. I think I will need to use snappyHex to join the blocks is this correct?
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Old   February 15, 2011, 17:40
Default
  #4
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Radko Bankras
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Hi,

Any other mesher would be easier to use for your design. I suggest to have a look at Salome for drawing, meshing, and exporting to Foam via ideasUnvToFoam. This will allow you to perform the logical actions of subtracting two solids, like I guess you are trying to achieve.

As an example of how the structure should be defined in blockMesh (for all I know), I have modified your file and added some extra points. Note that your AER structure has not been put in yet. It will take a few more hours to do so. Make sure the patches are defined in clock-wise direction when looking from inside the mesh.
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.7.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
convertToMeters 0.146;

vertices
(
  (0 241.3 0) //0
  (0 0 0) //1
  (0 -12.7 0) //2
  (0 -1524 0) //3
  (279.4 -12.7 0) //4
  (279.4 0 0) //5
  (292.1 38.1 0) //6
  (292.1 -313.6926357352644 0) //7
  (304.8 38.1 0) //8
  (304.8 13.51505771044411 0) //9
  (304.8 0 0) //10
  (304.8 -304.8 0) //11
  (863.6 216.9016246183983 0) //12
  (863.6 -521.7016246183977 0) //13
  (867.943655820235 204.9675283344171 0) //14
  (867.943655820235 -509.767528334418 0) //15
  (7620 241.3 0) //16
  (7620 -1524 0) //17
  (279.1341 -12.7 12.1873) //18
  (279.1341 0 12.1873) //19
  (291.822 38.1 12.7412) //20
  (291.822 -313.6926357352644 12.7412) //21
  (304.5099 38.1 13.2952) //22
  (304.5099 13.51505771044411 13.952) //23
  (304.5099 0 13.29522) //24
  (304.5099 -304.8 13.2952) //25
  (862.7780 216.9016246183983 37.6697) //26
  (862.7780 -521.7016246183977 37.6697) //27
  (867.1176 204.9675283344171 37.8592) //28
  (867.1176 -509.767528334418 37.8592) //29
  (7612.7474 241.3 332.3797) //30
  (7612.7474 -1524 332.3797) //31
  (279.1341 -12.7 -12.1873) //32
  (279.1341 0 -12.1873) //33
  (291.822 38.1 -12.7412) //34
  (291.822 -313.6926357352644 -12.7412) //35
  (304.5099 38.1 -13.2952) //36
  (304.5099 13.51505771044411 -13.2952) //37
  (304.5099 0 -13.2952) //38
  (304.5099 -304.8 -13.2952) //39
  (862.7780 216.9016246183983 -37.6697) //40
  (862.7780 -521.7016246183977 -37.6697) //41
  (867.1176 204.9675283344171 -37.8592) //42
  (867.1176 -509.767528334418 -37.8592) //43
  (7612.7474 241.3 -332.3797) //44
  (7612.7474 -1524 -332.3797) //45
  (279.1341 241.3 12.1873) //46 new
  (279.1341 241.3 -12.1873) //47 new
  (279.1341 -1524 12.1873) //48 new
  (279.1341 -1524 -12.1873) //49 new
  (7612.7474 0 332.3797) //50 new
  (7612.7474 0 -332.3797) //51 new
  (7612.7474 -12.7 332.3797) //52 new
  (7612.7474 -12.7 -332.3797) //53 new
);

blocks
(
  hex (3 48 49 3 2 18 32 2) (20 1 20) simpleGrading (1 1 1) //0
  hex (1 19 33 1 0 46 47 0) (20 1 10) simpleGrading (1 1 1) //1
  hex (48 31 45 49 18 52 53 32) (100 1 20) simpleGrading (1 1 1) //2
  hex (18 52 53 32 19 50 51 33) (100 1 5) simpleGrading (1 1 1) //3
  hex (19 50 51 33 46 30 44 47) (100 1 10) simpleGrading (1 1 1) //4
);

patches
(
  wall Top
  (
    (0 46 47 0)
    (46 30 44 47)
  )
  wall bottom
  (
    (3 49 48 3)
    (48 49 45 31)
  )
  wall back
  (
    (31 45 53 52)
    (52 53 51 50)
    (50 51 44 30)
  )
  patch inlet
  (
    (2 18 32 2)
  )
  patch outlet
  (
    (1 33 19 1)
  )
  wall nub
  (
    (18 19 33 32)
  )
  wedge side1
  (
    (3 2 18 48)
    (1 0 46 19)
    (48 18 52 31)
    (18 19 50 52)
    (19 46 30 50)
  )
  wedge side2
  (
    (3 2 32 49)
    (1 0 47 33)
    (49 32 53 45)
    (32 33 51 53)
    (33 47 44 51)
  )
  empty zoinks
  (
    (3 2 2 3)
    (1 0 0 1)
  )
);

mergePatchPairs
(
);

Last edited by Radko; February 15, 2011 at 17:43. Reason: no comments
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Old   February 15, 2011, 18:01
Default
  #5
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William
Join Date: Feb 2011
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Posts: 33
Rep Power: 6
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Thanks for the help Radko.

I have been using gmsh for converting and meshing iges files which is ok, but I have been having problems with makeAxialMesh specifically collapseEdges. I also tried just reassigning the generic patches created in gmshToFoam into wedge type which did not work. Do you know of another way to make wedge geometry? Beyond that I tried a 3D test case icoFoam using the gmshToFoam mesh assigning the sides of the wedge as "walls" as well as the other patches. Except output as constant velocity 1.3 m/s and input as 0 pressure just to see what would happen and the solution wouldn't converge after about 10 steps. Maybe I should set it as a negative pressure on input? I am basically trying to model a vertical mixer I know the velocity in the volute due to an impeller, which I am simplifying. Eventually I will need to model this as interfoam as the top surface is exposed to air. So this looks like it is going to be a long time before I get any data that is worth anything. I will try out the revised geometry tomorrow and I'll let you know how it goes.
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