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CFD newbie January 29, 2008 15:58

Blocking in ICEM
 
Hi

What is the difference between deleting the block to tell ICEM that it is solid surface and its not suppose to mesh it, and creating part (create part with blocks) and then moving it VORFN. In either case we get a solid object so there is no difference right?

CFD newbie


Gerrit Groot January 30, 2008 05:09

Re: Blocking in ICEM
 
I don't know whether I understand you right. VORFN is a strange sort of non existing block family that the ICEM program seems to need (other mesh programs don't). The VORFN is unmeshable by definition, it's the emptyness that defines the border of the universe, while if you change the material of a block it's still meshable by turning on or off that material (for example in case of multidisciplinary design you will need this)

ICEM can be very annoying, I advice you to do the least possible operations to come to a blocking, try to avoid creating blocks for example. One may find oneself merging VORFN blocks for example in order to get rid of an edge at infinity, an awful example of a user adapting himself to "bad" software.

CFD newbie January 30, 2008 05:58

Re: Blocking in ICEM
 
Thanks for your reply Gerrit. After having experienced Gambit i was quite happy with ICEM actually. I am trying to generate a mesh over an airfoil, but for some reason it keeps meshing the inside of my airfoil. In order to avoid that am i suppose to delet the block of my airfoil or should i go on create parts and then blocking material to make it solid. Is there any difference between two approaches! I dont know if i managed to make myself clear this time.

Regards CFD newbie

gotang January 30, 2008 07:34

Re: Blocking in ICEM
 
There is no difference between moving a block to VORFN and deleting it as long as "Delete permanently" is turned off. In either case, there is still a conceptual block there - now in the part/family VORFN - but ICEM does not create a mesh. However, it will act as if the gridlines run through the middle (so a change to the number of nodes on one side of your aerofoil will change the number of nodes on the other as well), even though no mesh is generated within the solid portion.

However, if you turn "Delete permanently" on when you delete the block, there is a difference - namely that the gridlines will no longer run through your aerofoil and the two halves are disconnected. Generally speaking, you do not really want to do this, unless you need to delete a block in order to join other nodes around it to change the topology of your blocking.

Hope that helps!

CFD newbie January 30, 2008 08:20

Re: Blocking in ICEM
 
Yes that has cleared my doubt. Thanks

CFD newbie

Charles February 1, 2008 04:11

Re: Blocking in ICEM
 
Move that block inside the airfoil into VORFN, your friendly catch-all recycle bin.


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