Icem cfd Cartesian mesh method size proplem

mztcu · May 18, 2009, 13:50

hi everyone
first ı am sory for my english
my problem
I want do mesh with cartesian method. there are 8 surface and ı chose diffrent size for surfaces like 1m,3m,5m . when computed the mesh every surfaces size to be the smallest value 1m Icant use diffrent size. Anyone help me ? Thanks everything

ghorrocks · May 18, 2009, 20:02

Hi,

Have you done the ICEM tutorial examples. This sounds like a pretty basic problem to me, you need to learn the fundamentals.

Glenn Horrocks

mztcu · May 20, 2009, 14:25

I have not much time .
please some ona help me.
how I do diffrent size for surface at cartesian mesh

Jules · May 20, 2009, 18:45

Your problem is not specified very clearly but consider this:
For a cartesian mesh (block structured mesh), blocks sharing one edge (adjacent surfaces) must have equal number of nodes in the direction (i,j, or k) of that edge, because grid lines cannot "end" in the middle of the mesh, they have to go all the way through from one side to the other.
Probably for that reason, the mesher adjusts all the spacings to be the same, to ensure equal number of nodes.
How are you creating your mesh? From blocking (Pre-Mesh) or from surface mesh?

rogbrito · May 24, 2009, 19:56

I´d like to use this type of mesh, using a cartesian method, but it didn´t work out with my geometry. What is your geometry?

Rogerio.

Quote:

Originally Posted by mztcu

hi everyone
first ı am sory for my english
my problem
I want do mesh with cartesian method. there are 8 surface and ı chose diffrent size for surfaces like 1m,3m,5m . when computed the mesh every surfaces size to be the smallest value 1m Icant use diffrent size. Anyone help me ? Thanks everything

mztcu · May 25, 2009, 08:45

ı want simulate free surface around the ship hull.geomtry ship hull and sea like pool

PSYMN · May 26, 2009, 08:55

Your problem probably has to do with uniform sizes, but once you fix that, you will still have issues because your sizes are not powers of 2…

If you are generating a uniform mesh, then the smallest “max size” is applied to the entire model… This is probably your problem. Look at your settings carefully. I agree about trying a tutorial or two, they don’t take long each and would have got you going faster than waiting for a reply from us.

The other issue is that the Cartesian and Octree methods can’t give you every size, only powers of 2. In this case, you can’t have sizes 1, 3 and 5 in the same model because these are not powers of 2. You could have sizes 1, 2, 4, or sizes 1.5, 3, 6 or sizes 1.25, 2.5, 5. Get it?

mztcu · May 26, 2009, 23:43

thank you very much I will try

May 18, 2009, 13:50	Icem cfd Cartesian mesh method size proplem	#1
mztcu New Member onder Join Date: Mar 2009 Posts: 18 Rep Power: 17	hi everyone first ı am sory for my english my problem I want do mesh with cartesian method. there are 8 surface and ı chose diffrent size for surfaces like 1m,3m,5m . when computed the mesh every surfaces size to be the smallest value 1m Icant use diffrent size. Anyone help me ? Thanks everything

May 20, 2009, 14:25	help	#3
mztcu New Member onder Join Date: Mar 2009 Posts: 18 Rep Power: 17	I have not much time . please some ona help me. how I do diffrent size for surface at cartesian mesh

May 26, 2009, 08:55	Pure Cartesian vs. Unstructured Cartesian	#7
PSYMN Senior Member Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,663 Blog Entries: 1 Rep Power: 47	Your problem probably has to do with uniform sizes, but once you fix that, you will still have issues because your sizes are not powers of 2… If you are generating a uniform mesh, then the smallest “max size” is applied to the entire model… This is probably your problem. Look at your settings carefully. I agree about trying a tutorial or two, they don’t take long each and would have got you going faster than waiting for a reply from us. The other issue is that the Cartesian and Octree methods can’t give you every size, only powers of 2. In this case, you can’t have sizes 1, 3 and 5 in the same model because these are not powers of 2. You could have sizes 1, 2, 4, or sizes 1.5, 3, 6 or sizes 1.25, 2.5, 5. Get it?

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May 18, 2009, 20:02		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Hi, Have you done the ICEM tutorial examples. This sounds like a pretty basic problem to me, you need to learn the fundamentals. Glenn Horrocks

May 20, 2009, 18:45		#4
Jules Member Jules Bell Join Date: May 2009 Posts: 32 Rep Power: 16	Your problem is not specified very clearly but consider this: For a cartesian mesh (block structured mesh), blocks sharing one edge (adjacent surfaces) must have equal number of nodes in the direction (i,j, or k) of that edge, because grid lines cannot "end" in the middle of the mesh, they have to go all the way through from one side to the other. Probably for that reason, the mesher adjusts all the spacings to be the same, to ensure equal number of nodes. How are you creating your mesh? From blocking (Pre-Mesh) or from surface mesh?

May 25, 2009, 08:45		#6
mztcu New Member onder Join Date: Mar 2009 Posts: 18 Rep Power: 17	ı want simulate free surface around the ship hull.geomtry ship hull and sea like pool

May 26, 2009, 23:43		#8
mztcu New Member onder Join Date: Mar 2009 Posts: 18 Rep Power: 17	thank you very much I will try