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-   -   [ICEM] how can mesh this geometry ? (http://www.cfd-online.com/Forums/ansys-meshing/107096-how-can-mesh-geometry.html)

malay September 17, 2012 11:34

how can mesh this geometry ?
 
1 Attachment(s)
Hi all , sorry for this question , i am new in ICEM ...
how can mesh this geometry ?

triangular channel in rectangulat solid , water inside the triangular channel ...

http://www.cfd-online.com/Forums/att...1&d=1347895911

stuart23 September 17, 2012 11:43

Are both domains fluid? Ie the entire box minus the triangular prism is one domain and the triangular prism is a second domain?

The boxminus the triangular prism is the more interesting of the domains. There are two different topologies that spring to mind. The choice really comes down to your actual model; what surfaces are inlets/outlets/walls etc.? These will dictate the flow directions, then you can choose a mesh topology that aligns itself best with this.

The first potential topology is a simple 3D block split three times along the length, and the assosiate vertices to the corners of the triangle

The other potential topology is a C grid arond the triangular prism propogated out to the far walls. This will give you better alignment if the triangle is a source or a sink.


Stu

malay September 17, 2012 12:11

yes the entire box minus the triangular prism is one domain( solid ) and the triangular prism is a second domain( fluid)

malay September 17, 2012 12:42

thanks stuart23 for reply , can more explain ?

Far September 17, 2012 15:03

simple possible solution, four blocks

http://imageshack.us/a/img543/3503/3...0648140212.jpg

malay September 17, 2012 21:04

1 Attachment(s)
Quote:

Originally Posted by Far (Post 382205)
simple possible solution, four blocks

http://imageshack.us/a/img543/3503/3...0648140212.jpg

thanks Far.... I did this blocks but the mesh quality appeared poor , especially at the corner of triangular prism ...

diamondx September 17, 2012 22:47

1 Attachment(s)
that's why you need to add a Y-grid. it is the best suitable for those kinf of corners.
Take a look at the project i attached

malay September 17, 2012 23:00

Quote:

Originally Posted by diamondx (Post 382244)
that's why you need to add a Y-grid. it is the best suitable for those kinf of corners.
Take a look at the project i attached


thanks ali .... can explain to me how you take the block for tringular prism ?? i mean how to devide the geometry to 5 blocks ( one of them to triangular prism ) ......

thank you so much ..

diamondx September 17, 2012 23:07

take a look at this video:
http://www.youtube.com/watch?v=InyeCmEuUVM
y-grid is created, also some vertices are merged. everything you need is in this video.
time to go to sleep... see you tomorrow

malay September 17, 2012 23:09

Quote:

Originally Posted by diamondx (Post 382246)
take a look at this video:
http://www.youtube.com/watch?v=InyeCmEuUVM
y-grid is created, also some vertices are merged. everything you need is in this video.
time to go to sleep... see you tomorrow


thank you so much my bro ..... good night ...

Far September 18, 2012 06:13

slide the vertices of the middle downward to improve the quality. Or

1. Insert Y Block

2. Put O-grid

malay September 18, 2012 06:19

Quote:

Originally Posted by Far (Post 382292)
slide the vertices of the middle downward to improve the quality. Or

1. Insert Y Block

2. Put O-grid


thanks Far ..... i get confuse when i try to make Y-block

Far September 18, 2012 11:39

check this http://www.cfd-online.com/Forums/ans...tices-why.html

and http://www.cfd-online.com/Forums/ans...here-cube.html

malay September 18, 2012 11:41


thank you so much ...

Far September 18, 2012 12:03

Few snapshots for your case (you have fluid and solid regions ?)


http://imageshack.us/a/img16/8242/25012915.png

http://imageshack.us/a/img694/5915/74422280.png

http://imageshack.us/a/img267/9190/85138005.png

http://imageshack.us/a/img267/944/23293628.png

http://imageshack.us/a/img51/8597/16537348.png

http://imageshack.us/a/img840/7682/85598854.png

http://imageshack.us/a/img607/9600/97676964.png

malay September 18, 2012 23:18

yes i have fluid and solid regions ....

thanks bro

malay September 18, 2012 23:24

when i finish making mesh by ICEM with fluid and solid i read it by fluent , but in fluent only one zone appear ( solid ) why ???

Far September 19, 2012 01:06

Because you don't have the fluid region!!!

Right click on the parts then choose the last option (blocks). Rename to fluid and select the fluid blocks (blocks in Y-grid). Recreate premesh and convert to mesh. After that export the mesh and import into Fluent. You are done. :)

malay September 19, 2012 01:17

Quote:

Originally Posted by Far (Post 382463)
Because you don't have the fluid region!!!

Right click on the parts then choose the last option (blocks). Rename to fluid and select the fluid blocks (blocks in Y-grid). Recreate premesh and convert to mesh. After that export the mesh and import into Fluent. You are done. :)

really i thank you so much ..... i get it

Far September 19, 2012 02:20

Quote:

Originally Posted by malay (Post 382238)
I did this blocks but the mesh quality appeared poor , especially at the corner of triangular prism ...

When you have the triangular prisms, dont compare their quality to hexa. With prism, quality of 0.01 is also good enough

Here I am quoting one of the Simon's post regarding quality. http://www.cfd-online.com/Forums/ans...rism-mesh.html post # 15

Quote:

If you haven't seen the inverted issue, then no worries... It happens only in 13.0 for redistribute prism, but is already fixed... In the mean time, the work around is to redistribute using the "Move => Redistribute Prisms" command. There isn't any more to tell.

Min tetra quality should probably be above 0.2, but if you have some below, it is probably fine, particularly in a non critical area. CFX is pretty robust, you could try as low as 0.05.

The Prism metric is really harsh in ICEM CFD. If you can get above 0.01, it will probably run fine in CFX... You could even go lower. (Maybe others can comment on their worst mesh that converged)...

Hexa, you are usually looking at min angle and aspect ratio... We shoot for an angle over 18, but will take anything over 9.


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