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-   -   [ICEM] Mesh generation (http://www.cfd-online.com/Forums/ansys-meshing/116850-mesh-generation.html)

noorul April 26, 2013 08:57

Mesh generation
 
hello..
i have to do a simulation over a pleated insect wing. i'm using ICEM CFD 14.0 for mesh generation. when i select Robust Octree as mesh method, mesh is easily created. for more smooth transition when i select Delaunay as mesh method, no mesh is created. i have tried so many times. please help me out.
Thank You..

Far April 26, 2013 09:47

For denauly you need surface mesh.

So you should do like:

1. Set mesh sizes

2. generate octree mesh

3. Delete volume mesh

4. smooth surface mesh

5. Now compute danauly mesh.

noorul April 30, 2013 13:44

1 Attachment(s)
Thanks a lot Sir..
i tried so many times, but the problem remains there.
however I succeeded in generating delaunay mesh over simple geometries like 3D circular cylinder etc.
i think very small thickness of my wing might have something to do with this problem.
Please suggest me what to do now..??
I have attached a image showing a series of thin pleated wing sections i have used to create the wing surface..
Thanks once again..

Far April 30, 2013 18:21

is this a image of your wing or you will skin all these tubes to make a wing surface?

stuart23 April 30, 2013 19:08

For Patch Dependent surface meshing, you need to have well connected topology. First run build topology and ensure that all of your curves turn red.

noorul April 30, 2013 22:14

1 Attachment(s)
Sir I have created a surface as shown in the image.

noorul April 30, 2013 22:17

Yes Sir, I have taken a tolerance value of 0.1 and ran the build topology. All my surfaces are with in tolerance and curves turned red.

Sanju May 3, 2013 10:41

Hello....I'm new to CFD. I want to know what is the advantage of delaunay over octree mesh. Why we are going for delaunay?
Thanks

Far May 3, 2013 12:22

Actually octree is robust method, means you don't need any surface mesh and it rarely fails to generate decent mesh. But problem with octree is that if will make mesh where:

1. Where size change is abrupt i.e growth is not smooth

2. No of nodes are too high.

While with denauly you have smooth transition in volume mesh.

So best option is to generate volume mesh with octree, delete volume mesh and leave surface mesh, smooth surface mesh and compute denauly.

There are many threads where Simon discussed both methods in great details.

http://www.cfd-online.com/Forums/ans...rmula-one.html

Sanju May 6, 2013 01:55

Sir,

Thanks for the reply.It wud be great help if u cud give me a slight guidance.

In my case I hav to mesh an inducer of a centrifugal pump (similar to the propeller of a ship) and the entry of flow into the inducer is not symmetic like in propeller.

So I cant use a sector of inducer and mesh, instead I hav to use the entire geometry. So which method should i go for?.. hexa meshing or tetra meshing. The number of nodes is also a concern for me and I'm using ANSYS paltform.

Thanks

Far May 6, 2013 02:54

Sanju, Can you please start a new thread with proper title...

keyhan June 21, 2013 08:43

help
 
can any one give a tutorial for a 2d centrifugal pump how to make a mesh and how to analysis in fluent from 0 to finsish plz help,,please send to keyhan_mec@yahoo.com

Far June 23, 2013 02:42

divide the domain (blocking) for the mapped meshing and for tetra mesh set sizes on surface/curves and compute mesh.


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