[ICEM] Meshing strategy for 3D sharp point

D-willism · October 10, 2012, 22:55

Do you guys think this sharp point can be meshed well with hexa grids? any suggestions on the meshing strategy?

Looking forward to your replies, thank you!

diamondx · October 10, 2012, 23:03

hmmm very difficult...
I once face a sharp geometry but not like this one. i had to use y-grid.
take a look at this video, there is no sound but i added annotations:
http://www.youtube.com/watch?v=nuiRkZqaEz4
try it with this method , come back to us here let us know how was it

diamondx · October 10, 2012, 23:25

wait a second; y-grid needs to be applied to triangular shapes... yours is not...
just realized that while laying in my bed

May i ask what are you trying to model ?

D-willism · October 11, 2012, 00:01

Modelling? you mean CFD analysis? I am modelling the air flowing across this cone shape, so I have a cylinder enclosing the cone shape. but around the sharp point, the aspect ratio and skewness of the grids are kind of poor. Does this answer your doubt?

diamondx · October 11, 2012, 14:40

what software did you use to generate your mesh, can you post some screenshots ?

davidwilcox · October 12, 2012, 01:04

I once meshed a geometry with a sharp end. I used the quarter O grid blocking method for the sharp end. Maybe you can give that a go.

D-willism · October 12, 2012, 07:44

Quote:

Originally Posted by diamondx

what software did you use to generate your mesh, can you post some screenshots ?

I am using ICEM CFD. Three pisc show the geometry, blocking and poor quality grids. all the poor quality grids gather around and are due to the wedge-like blocks at the right bottom of the rectangle geometry. If I can get rid of these two wedge-shape blocks which means only four blocks left around the half-cone shape, the quality of the grids should be very high. Any ideas or suggestions how to achieve this?

Best Regards

D-willism

D-willism · October 12, 2012, 07:45

I will try that once I get to university tomorrow. thx

Far · October 12, 2012, 11:56

share geometry

D-willism · October 12, 2012, 20:42

Quote:

Originally Posted by Far

share geometry

zip file includes 2 geometries I am trying now.

Best Regards

D-willism

Far · October 13, 2012, 03:43

For rectangular enclosure blocking is simple. Min quality is 0.9, however min angle is 16.9. Try solving this mesh in Fluent.

Circular Enclosure: The blocking of this geometry with circular enclosure is felt difficult to me always. Can someone guide us how to handle the circular domain in efficient way?

Far · October 13, 2012, 03:56

Please find enclosed files (.prj, .tin, .blk). After some adjustments in blocking min angle is greater than 18.

Far · October 13, 2012, 04:02

Quote:

Originally Posted by D-willism

I am using ICEM CFD. Three pisc show the geometry, blocking and poor quality grids. all the poor quality grids gather around and are due to the wedge-like blocks at the right bottom of the rectangle geometry. If I can get rid of these two wedge-shape blocks which means only four blocks left around the half-cone shape, the quality of the grids should be very high. Any ideas or suggestions how to achieve this?

Best Regards

D-willism

The elements are prism and ICEM is very harsh on prisms quality (Simon told it in many posts, search you can find one). So give it try with your mesh also in solver and see what happens in terms of convergence with both meshes

D-willism · October 13, 2012, 04:27

Thank you SO SO SO much! You've been very kind

D-willism · October 13, 2012, 05:43

When I opened the project file using ICEM CFD 14.0, it required a attribute file? But obviously it is not in the file you posted, does it really matter? And hmm... because you adjusted the angle from 16 to 18, the min quality degrades and not the same as what you show us in the picture. Could you please post the files before you made angle adjustments please if you can? Thank you so much!!

Best Regards

D-willism

Far · October 13, 2012, 06:15

Quote:

When I opened the project file using ICEM CFD 14.0, it required a attribute file? But obviously it is not in the file you posted, does it really matter?

This file does not matter for the blocking. It has other functions.

In this mesh min quality is 0.8 and min angle is 18. Please uncheck the solid part if it is turned-on...

D-willism · October 13, 2012, 23:05

Thank you Far! I am now trying to block and mesh the geometry without having those wedge-shape blocks at the bottom of the geometry, which means only four blocks left enclosing the semi-cone (solid, as you named in the file). Do you think it is feasible?

Best Regards
D-willism

Far · October 14, 2012, 01:45

I am sending you two project files (both include .prj, .blk and .tin). That is before merging the vertices and then after merging the appropriate vertices. Now you can apply the Y-block option on two wedge shapes blocks to get what I posted earlier.

PS. I have also used the build topology command to create the points at the required locations.
I have also used the ungroup curves command, available in blocking association panel

Far · October 14, 2012, 02:07

please see these five files, containing five steps from the creating the initial block to the final mesh. Quality is around 0.8 and min angle is 18

D-willism · October 14, 2012, 02:50

Thank you Far! what I was trying to say is: do you reckon if it is feasible or possible to block the domain into four sub blocks, instead of including small wedge-like blocks as well underneath the sub blocks (big/major ones)?

Best Regards
D-willism

October 10, 2012, 23:03		#2
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	hmmm very difficult... I once face a sharp geometry but not like this one. i had to use y-grid. take a look at this video, there is no sound but i added annotations: http://www.youtube.com/watch?v=nuiRkZqaEz4 try it with this method , come back to us here let us know how was it __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

October 10, 2012, 23:25		#3
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	wait a second; y-grid needs to be applied to triangular shapes... yours is not... just realized that while laying in my bed May i ask what are you trying to model ? __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

October 11, 2012, 14:40		#5
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	what software did you use to generate your mesh, can you post some screenshots ? __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

October 12, 2012, 01:04		#6
davidwilcox Senior Member david Join Date: Oct 2012 Posts: 142 Rep Power: 13	I once meshed a geometry with a sharp end. I used the quarter O grid blocking method for the sharp end. Maybe you can give that a go. D-willism likes this.

October 13, 2012, 03:43		#11
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	For rectangular enclosure blocking is simple. Min quality is 0.9, however min angle is 16.9. Try solving this mesh in Fluent. Circular Enclosure: The blocking of this geometry with circular enclosure is felt difficult to me always. Can someone guide us how to handle the circular domain in efficient way? D-willism likes this. Last edited by Far; July 18, 2014 at 05:59.

October 11, 2012, 00:01		#4
D-willism New Member Fan Derrick He Join Date: Jul 2012 Location: Sydeny Posts: 14 Rep Power: 13	Modelling? you mean CFD analysis? I am modelling the air flowing across this cone shape, so I have a cylinder enclosing the cone shape. but around the sharp point, the aspect ratio and skewness of the grids are kind of poor. Does this answer your doubt?

October 12, 2012, 07:45		#8
D-willism New Member Fan Derrick He Join Date: Jul 2012 Location: Sydeny Posts: 14 Rep Power: 13	I will try that once I get to university tomorrow. thx

October 12, 2012, 11:56		#9
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	share geometry

October 13, 2012, 04:27		#14
D-willism New Member Fan Derrick He Join Date: Jul 2012 Location: Sydeny Posts: 14 Rep Power: 13	Thank you SO SO SO much! You've been very kind

October 13, 2012, 05:43		#15
D-willism New Member Fan Derrick He Join Date: Jul 2012 Location: Sydeny Posts: 14 Rep Power: 13	When I opened the project file using ICEM CFD 14.0, it required a attribute file? But obviously it is not in the file you posted, does it really matter? And hmm... because you adjusted the angle from 16 to 18, the min quality degrades and not the same as what you show us in the picture. Could you please post the files before you made angle adjustments please if you can? Thank you so much!! Best Regards D-willism

October 13, 2012, 23:05		#17
D-willism New Member Fan Derrick He Join Date: Jul 2012 Location: Sydeny Posts: 14 Rep Power: 13	Thank you Far! I am now trying to block and mesh the geometry without having those wedge-shape blocks at the bottom of the geometry, which means only four blocks left enclosing the semi-cone (solid, as you named in the file). Do you think it is feasible? Best Regards D-willism

October 14, 2012, 01:45		#18
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	I am sending you two project files (both include .prj, .blk and .tin). That is before merging the vertices and then after merging the appropriate vertices. Now you can apply the Y-block option on two wedge shapes blocks to get what I posted earlier. PS. I have also used the build topology command to create the points at the required locations. I have also used the ungroup curves command, available in blocking association panel

October 14, 2012, 02:50		#20
D-willism New Member Fan Derrick He Join Date: Jul 2012 Location: Sydeny Posts: 14 Rep Power: 13	Thank you Far! what I was trying to say is: do you reckon if it is feasible or possible to block the domain into four sub blocks, instead of including small wedge-like blocks as well underneath the sub blocks (big/major ones)? Best Regards D-willism

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