[ICEM] Prism Mesh on a semisphere

Will Anderson · June 2, 2013, 13:27

Why does ICEM produce an erroneous Prismmesh on this simple semisphere?

Replay script and graphical result attached.

diamondx · June 2, 2013, 18:12

the problem resides in the geometry. make sure all the surfaces are checked for prism...
You can share your project so we can investigate with you...

Will Anderson · June 2, 2013, 18:15

Thank you diamondx.
In fact, i have found a different but related problem.
The symmetry surface and the ball must share an intersection curve.
They hadn't before.
Once the intersection curve between the symmetry plane and the ball was implemented (Geometry->Curve->Intersection of Surfaces), the mesh looks quite normal.

PSYMN · June 2, 2013, 21:11

Yes, but the fix is simpler than that...

The bad intersection caused the problem...
Will_Anderson_Prism_1.jpg
This is because your small circle was offset a bit, which crumbled the edges so prisms couldn't form.

Here you can see that the prisms are fine away from the bad edge...
Will_Anderson_Prism_2.jpg
See here in the script... Why did you set the center of the sphere 1 unit below the symmetry plane?
Will_Anderson_Prism_3.jpg
Once I fixed that first line (to go from 0 to 1 instead of -1 to 0), it worked no problem...
Will_Anderson_Prism_4.jpg

Will Anderson · June 2, 2013, 23:30

Thanks Simon. Why did I offset the sphere center by 1 mm? In order to be more sure that the surfaces intersected.

Thanks everyone.

PSYMN · June 3, 2013, 10:31

Quote:

Originally Posted by Will Anderson

Thanks Simon. Why did I offset the sphere center by 1 mm? In order to be more sure that the surfaces intersected.

Thanks everyone.

OK, but it was probably unnecessary. ICEM CFD can handle some misalignment, but in this case, it was just too great compared to the mesh size.

June 2, 2013, 18:12		#2
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 28	the problem resides in the geometry. make sure all the surfaces are checked for prism... You can share your project so we can investigate with you... __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

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June 2, 2013, 18:15		#3
Will Anderson Member W.N. Anderson Join Date: Jul 2010 Location: Zürich, Switzerland Posts: 46 Rep Power: 15	Thank you diamondx. In fact, i have found a different but related problem. The symmetry surface and the ball must share an intersection curve. They hadn't before. Once the intersection curve between the symmetry plane and the ball was implemented (Geometry->Curve->Intersection of Surfaces), the mesh looks quite normal.

June 2, 2013, 23:30		#5
Will Anderson Member W.N. Anderson Join Date: Jul 2010 Location: Zürich, Switzerland Posts: 46 Rep Power: 15	Thanks Simon. Why did I offset the sphere center by 1 mm? In order to be more sure that the surfaces intersected. Thanks everyone.