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October 21, 2011, 03:40 |
hybrid mesh of tangential inlet
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#1 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
I want to make hybrid mesh for cyclone separators. i have attached picture of my cyclone. i have generated the multiblock structured mesh as shown in picture. if i mesh the inlet with sructured mesh then elements in the entry region are very skewed and quality is low. so i want unstructured mesh at inlet. please help me..
i dint know how to connect the nodes of structured mesh to the unstructured mesh at inlet. please help me. |
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October 21, 2011, 05:20 |
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#2 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
Hi
In ICEM CFD you can merge mesh in few different ways. You can generate grids separately, then load and merge both. In this way you will have non-conformal mesh. To connect nodes on contact surface go to Edit Mesh->Merge Nodes->Merge volume meshes. After this you can smooth theta elements using option Smoot mesh globally. Other method is to leave hex mesh on contact surface and then you can generate unstructured mesh with enable Use Existing Mesh Parts and selected part contain contact surface with in. After this operation reread both meshes and connect nodes using merge nodes by tolerance. Set tolerance to some small value because these nodes have the same coordinates. You can also watch this tutorial: http://www.youtube.com/watch?v=KabKF...eature=related Regards |
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October 21, 2011, 06:08 |
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#3 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
thank you twix for your help... i had already gone though that tutorial but if i mesh like that then my element quality at tangential inlet is very poor. that's why i prefer hybrid mesh. is there any other way to mesh tangential inlet part.
also could you please give me the example to merge the mesh. i will very thankful to you. please help. also in volume merge option i come across two options. 1. merge surface mesh part & 2. frozen volume mesh part. what to do with these options. which part i have to select in that tabs. please help. Last edited by arjun3020; October 21, 2011 at 06:56. |
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October 21, 2011, 07:01 |
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#4 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
You can also use quarter O-grid block but probably in selected areas you will get bad element quality.
Regards Last edited by Twix; October 21, 2011 at 07:16. |
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October 21, 2011, 07:06 |
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#5 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
thank you. as you said i am getting bad quality in selected areas. that's why i am going for hybrid mesh.
i found following difficulties. in volume merge option i come across two options. 1. merge surface mesh part & 2. frozen volume mesh part. what to do with these options. which part i have to select in that tabs. please help. |
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October 21, 2011, 07:31 |
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#6 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
1. In this tab you should select the surface mesh parts to be merged (interface between two meshes).
2. You can leave it empty because hex mesh is frozen by default. |
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October 23, 2011, 12:50 |
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#7 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
hi... i tried as per your suggestions but i am not able to get hybrid mesh.
i am attaching simple cube geometry. i mesh half part with blocking (hexa), and remaining part with unstructured tetra. then i load mesh from blocking it shows dialog box showing 'mesh is already present' then i click on merge tab. then it shows mesh like image 1, then i go for merging option from edit mesh but mesh is not good (image 2) i thing i am doing some mistakes. could you please tell me the step by step procedure in detail. please help. i will be very thankful to you. |
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October 24, 2011, 03:15 |
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#8 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
Hi,
First step is to build topology for your geometry. Then, create new part e.g. INTERFACE and put there contact surface, between 2 domains, only. Generate your meshes, load and merge them, then go to Merge Nodes->Merge volume mesh and in tab “Merge surface mesh parts” select your new part containing contact surface, click Apply and everything should be ok. Regards and have fun |
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October 24, 2011, 10:42 |
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#9 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
hi. i tried to get hybrid mesh. i build topology its fine. geometry is ok.then i mesh half part with hexas. while meshing remaining half part it shows that your geometry has a hole. them i press repair. but its not working. please help.
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October 25, 2011, 02:01 |
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#10 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
Hi
Probably you didn’t include part with contact surface to parts selected to meshing. This surface have to be mesh in both (hex and theta) grids. Also you have to create material point to generate theta volume mesh. Regards |
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October 25, 2011, 08:51 |
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#11 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
hi.. finally i got it. thank you so much for your help.
but while meshing my cyclone problem i find difficulties, i am attaching the hybrid mesh of cyclone. it is not good at inlet entry. what should i do to have good quality mesh for cyclone. |
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October 26, 2011, 00:30 |
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#12 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
Hi Michal,
you have also advice me to use the quarter o-Grid, i have done few steps. but i cant proceed. i have attached picture for your reference. now while creating y block (quarter o- grid) it ask to select 6 vertices. which vertices should i select. |
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October 26, 2011, 00:37 |
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#13 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
Sorry here is the attachment.
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October 26, 2011, 01:46 |
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#14 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
Hi
Check in help, there is a picture showing vertices you should select and the order of selection. Regards |
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October 26, 2011, 03:31 |
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#15 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
i had already check the help but its not working. i followed the instruction but its not working. i managed to get y block as shown in picture, but i have problem in association of that y block.
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October 26, 2011, 03:39 |
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#16 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
also could you please help me in former issue. see reply number 12.
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October 26, 2011, 04:11 |
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#17 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
Submit your project, i will see what is wrong.
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October 26, 2011, 05:53 |
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#18 |
Member
arjun
Join Date: Oct 2011
Location: Tokyo, JAPAN
Posts: 66
Rep Power: 14 |
Hi, i am sending you my project, please see to it. thanks.
i am sending you my trial project. i am actually working on cyclone. i will mesh the cyclone as per trial project. |
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October 26, 2011, 07:27 |
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#19 |
Member
Michal
Join Date: Mar 2009
Posts: 38
Rep Power: 19 |
Hi,
I took a look at your project and you didn’t merge vertices marked in the picture. To do so you have to go to Blocking -> Merge Vertices-> Merge Vertices by Number or Tolerance, but as I wrote earlier you will have some bad elements. Regards |
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October 26, 2011, 08:30 |
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#20 |
Senior Member
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 21 |
Look at the project attached. It increases a little bit the quality.
At least, yout min angle is 18°, which is not that bad |
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