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user0314 September 19, 2011 13:47

ICEM CFD- Error: prism terminated prematurely
I am trying to mesh a 3D geometry in ICEM and create prism layers. I am using tetra unstructured mesh.

I first generate the mesh, and run mesh check. There are no errors. Next I run prism and get the following error:

prism: swap. C:616: base_vertex* check_collapse(base_vertex*,base_vertex*,unstruc_m esh*,check_collapse_opts*,merge_data*): Assertion e1->ptwin()->ptwin() = e1' failed.
Application is finished
Error: prism terminated prematurely.

Does anybody have an idea what this error could mean?


BrolY September 20, 2011 05:43

We need more info such as pictures of the geometry or how you proceed to specify your prism parameters !

user0314 September 20, 2011 09:49

more information and reply
I am simulating is a 3D pi slice of a disk. There is a pi-shaped column of fluid above the pi slice. The disk is filled with a porous material and there is a suction cavity below the porous material.

I specify the prism parameters as:

initial height: 0.001
height ratio: 1.1
number of prism layers: 20

There are prism layers along all of the walls, as well as on the surface of the disk.

user0314 September 20, 2011 09:53

Picture of geometry
1 Attachment(s)
Attached is a picture of geometry.

user0314 September 20, 2011 10:03

More prism info
min prism quality: 0.00001
ortho weight: 0.5
fillet ratio: 0.35
max prism angle: 176

BrolY September 20, 2011 10:05

Did you try to create only 1 prism layer to see what's going on ?
And post the picture of the result, it may help ;)

user0314 September 20, 2011 10:16

pic of result
1 Attachment(s)
Here is a zoomed in picture of the result. It looks like it created 1 layer correctly. But creating multiple layers is causing a problem.

If you need a different view, just let me know!

user0314 September 20, 2011 10:23

splitting prism layer
I tried splitting the prism layer. Seems to work, but how come I can't create multiple layers at one time? I would like to be able to do that.

Is there advantage/disadvantage to either method?

BrolY September 20, 2011 10:55

I don't know why you can't create multiple layers at one time. Maybe ICEM acn't handle so many layers with your geometry. Maybe at some point, there are intersections which can't be fixed.

Make a research on this forum about that topic, you will find a lot of answers to your questions ;)

PSYMN September 20, 2011 13:21

It just won't fit...
In the image you showed, there is a thinner lower region that is a green/teal color... This region is only 3 elements deep. If you try to grow too many layers, the corner of the prisms will come up at a 45 degree angle and will eventually get to close to the interface between the green/teal and the blue/cyan regions... Since that is a change in material, it represents a hard wall and prism will get stuck or break down...

You are not stuck with 1 layer though... Try 3 or 5 and see how it goes. Check and corner and see how tight things are getting to decide if you can try with a greater number of layers...

Some times the number of layers you think you want just won't fit...

You could even try different numbers of layers in different regions based on what the geometry can accommodate...

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