[ICEM] Wrong Prism Direction

max3.2 · May 23, 2011, 08:16

Hi guys,

I'm tying to mesh a duct flow with ICEM Tet and 1 prism wall layer which I then want to split up. This is no problem so far. But when i split the layer to set an initial height, the initial height is set at the volume side, not the wall side. i have done prism mesh before, but never had this error. my material point is inside the volume(tet works perfectly). is there a way to turn direction for prism layers?

regards
max

jeevankumarb · May 24, 2011, 06:45

please can you post some images to better understand your problem

max3.2 · May 24, 2011, 08:53

I will do later, cant acces my server atm.

EDIT:

There we go. Pic 1 overview, Pic 2 prism front view, Pic 3 splitted view. Problem: The thinner Prism are at the Flow side, but they should be at wall side...
Hope this helps

regards
Max

ayush · June 14, 2011, 00:45

Hey max, if i understood your problem properly, it is just that the gap between the initial height and the final specified prism height is not sufficient enough for the number of layers you want to grow. Try computing the Height ratio, it should be less than 1. So simply reduce the number of layers to get that ratio upto 1, and then later split the prisms to get your requisite layers.

max3.2 · June 19, 2011, 16:04

Hmm thanks but i think i meant something else. As you can see, the growth ratio and initial height is right, if the wall (where the boundary layer is i want to resolve) would be on the right (in the picture above). but it is on the left, so theres the problem.

(I already changed to a block mesh. but still im interested in finding my mistake)

regards
max

Prakash.Paudel · August 16, 2011, 22:34

edit mesh ; move nodes; redistribute prism should do the trick

max3.2 · August 19, 2011, 05:54

Hi,

thank you. Since i used another mesh, I evaded this problem. But i tested it and it worked!

PSYMN · August 20, 2011, 20:09

Yes, sorry, we screwed it up at 13.0

When you split prism, it does it in reverse order so the fattest layer is on the inside...

We had redone the split prism (enhanced it in a bunch of ways with a whole new more flexible algorithm) and we screwed that one thing up.

The fix is to go one more step to Edit mesh => Move nodes => Redistribute Prism. That will sort you out.

This problem was corrected for 14.0, due out later this year.

May 23, 2011, 08:16	Wrong Prism Direction	#1
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 15	Hi guys, I'm tying to mesh a duct flow with ICEM Tet and 1 prism wall layer which I then want to split up. This is no problem so far. But when i split the layer to set an initial height, the initial height is set at the volume side, not the wall side. i have done prism mesh before, but never had this error. my material point is inside the volume(tet works perfectly). is there a way to turn direction for prism layers? regards max

May 24, 2011, 08:53		#3
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 15	I will do later, cant acces my server atm. EDIT: There we go. Pic 1 overview, Pic 2 prism front view, Pic 3 splitted view. Problem: The thinner Prism are at the Flow side, but they should be at wall side... Hope this helps regards Max Last edited by max3.2; May 24, 2011 at 11:31. Reason: pictures added

August 20, 2011, 20:09	Defect... Fixed.	#8
PSYMN Senior Member Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,663 Blog Entries: 1 Rep Power: 47	Yes, sorry, we screwed it up at 13.0 When you split prism, it does it in reverse order so the fattest layer is on the inside... We had redone the split prism (enhanced it in a bunch of ways with a whole new more flexible algorithm) and we screwed that one thing up. The fix is to go one more step to Edit mesh => Move nodes => Redistribute Prism. That will sort you out. This problem was corrected for 14.0, due out later this year. __________________ ----------------------------------------- Please help guide development at ANSYS by filling in these surveys Public ANSYS ICEM CFD Users Survey This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)... CFD Online Users Survey

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
udf error	srihari	FLUENT	1	October 31, 2016 14:18
Getting prism to inflate into mixed tet-hex meshes	Joe	CFX	16	October 10, 2011 07:06
ICEM Prism Layer transition between surface with prism layers and one without	TWaung	ANSYS Meshing & Geometry	2	October 12, 2009 14:56
ICEM - Prism Tool Problem	carpe85	CFX	0	February 10, 2009 12:25
Icemcfd: Preventing prism inflation collisions?	Joe	CFX	1	July 31, 2007 09:13

May 24, 2011, 06:45		#2
jeevankumarb Member jeevan kumar Join Date: Mar 2009 Posts: 88 Rep Power: 17	please can you post some images to better understand your problem

June 14, 2011, 00:45		#4
ayush New Member A-Vdia Join Date: Jun 2011 Posts: 5 Rep Power: 14	Hey max, if i understood your problem properly, it is just that the gap between the initial height and the final specified prism height is not sufficient enough for the number of layers you want to grow. Try computing the Height ratio, it should be less than 1. So simply reduce the number of layers to get that ratio upto 1, and then later split the prisms to get your requisite layers.

June 19, 2011, 16:04		#5
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 15	Hmm thanks but i think i meant something else. As you can see, the growth ratio and initial height is right, if the wall (where the boundary layer is i want to resolve) would be on the right (in the picture above). but it is on the left, so theres the problem. (I already changed to a block mesh. but still im interested in finding my mistake) regards max

August 16, 2011, 22:34		#6
Prakash.Paudel New Member Prakash Paudel Join Date: May 2010 Location: Toronto Posts: 25 Rep Power: 15	edit mesh ; move nodes; redistribute prism should do the trick

August 19, 2011, 05:54		#7
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 15	Hi, thank you. Since i used another mesh, I evaded this problem. But i tested it and it worked!