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-   -   [GAMBIT] hydrocyclone Mesh Quality. (http://www.cfd-online.com/Forums/ansys-meshing/109716-hydrocyclone-mesh-quality.html)

Al-Hashimi November 24, 2012 14:32

hydrocyclone Mesh Quality.
 
https://docs.google.com/open?id=0B1F...EplUG4zVFVaOUk

Hi Everyone,

Im working on the meshing of hydrocyclone with gambit. I finished the mesh but would if anyone can advise me if my work in correct or these is some lacks?
I went to mesh exam and set to range from 0.9 to 1, there are 5 grids appeared in face 14. Should I change the geometry by lifting this face or I can use sweep face in the z direction by 1 unit.
For all volumes I set the aspect ratio by 1, should I change it to 0.45?
Note: this work is a two phase flow (water contains sand particles). I meshed all faces by Hybird/Tgrid.

please see attached file in the link below on google documents:
https://docs.google.com/open?id=0B1F...0hSR0xKdGpPbW8


Highly appreciate any assistance
Thanks for Mr. mAx for assisting me.

Osamah Al-Hashimi

-mAx- November 28, 2012 15:02

your link doesn t work

Al-Hashimi November 29, 2012 04:42

1 Attachment(s)
Here the link sir ... it is the same file i sent you before and you checked it ...
I just like to view the procedure for solving the two problems you spcificed.
is this procedure oK?
https://docs.google.com/open?id=0B1F...0hSR0xKdGpPbW8

REGADING the aspcet ratio, Please see attached pic when i change the Aspect Ratio from 1 to 0.45 ... can i keep the Aspect ration by 1?

Thank you

Attachment 17328

-mAx- November 30, 2012 02:20

1 Attachment(s)
Again your problem are only on edge 5, edge 9 end edge 12
You can fix your both first issues by giving more nodes on edge 5 and edge 9
Edge 12 issue can be fixed if you sweep face 14 in z-direction (small vector). Then sharp angle at vertex 12 wil disppear if you suppress edge 12 (by merging surface 8 with new surface from sweep)
Attachment 17349

Al-Hashimi November 30, 2012 07:41

3 Attachment(s)
Many Thanks Freind
These problems appears when I try to merge face 8 with the new face from the sweep (face 20)
Error: Tried to merge faces face 8 and another from the list that are not connected.
I tried face 14 with 20 same error appeared.
I tried face 8 & 14 & 19& 20 this error appeared:
Error: tried to merge faces face 8 and face 19 with different upper topology or with nonmanifold neighbors (share the common boundary with another face).

Attachment 17356

Attachment 17357

Attachment 17358


-mAx- November 30, 2012 07:48

before you merge both surfaces, you need of course to merge both volumes

Al-Hashimi November 30, 2012 08:47

2 Attachment(s)
Thank you very much
I merged the two volumes a v_voulme.6 created mesh is done but is it ok?
Attachment 17359

Attachment 17360

-mAx- November 30, 2012 08:49

examine mesh and check quality (skewness < 0.9 should be ok for tetra mesh)

Al-Hashimi November 30, 2012 09:01

1 Attachment(s)
it is 0.74 ... Please see attached picture.
Is the vertual volume a problem?
Many thanks sir for your time and for advicing me ... thank you very much

Attachment 17361

Al-Hashimi November 30, 2012 09:15

should i change the vertual volume to real? can i say that i have accepted quality mesh to work on a two phase flow in fluent.
many thanks many times

-mAx- November 30, 2012 09:59

virtual isn t a problem
you can go and solve

Al-Hashimi November 30, 2012 13:42

Thank you verrrrrrrrrrrrrrrry much ... god save youuu.

Al-Hashimi December 3, 2012 15:17

Hi, i made a new geometry ... and re meshed it in Gambit
In Fluent i made a <report quality> for both meshes , i got this results:

Mesh Quality (for the geomety you assisted me in):

Mesh Quality:
Applying quality criteria for tetrahedra/mixed cells.
Maximum cell squish = 7.24566e-001
Maximum cell skewness = 9.54236e-001
Maximum aspect ratio = 1.65974e+001

***************************************

Mesh Quality for the geometry i made (the new one):
Applying quality criteria for tetrahedra/mixed cells.
Maximum cell squish = 7.24566e-001
Maximum cell skewness = 9.54236e-001
Maximum aspect ratio = 1.65974e+001


is there a problem in the Maximum cell skewness of the second geometry?

Many thanks freind for your continouse assistance ...

Al-Hashimi December 3, 2012 16:02

i have enhanced the mesh of the new geometery, the result is:

Mesh Quality:
Applying quality criteria for tetrahedra/mixed cells.
Maximum cell squish = 7.24566e-001
Maximum cell skewness = 7.92745e-001
Maximum aspect ratio = 1.65974e+001


I think it is much better ... Many thanks mAx :D

-mAx- December 4, 2012 02:01

Quality should be ok. Since you don't get a "Grid Check Failed" you can go and solve.


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