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-   -   [ICEM] problem with blocks (http://www.cfd-online.com/Forums/ansys-meshing/122910-problem-blocks.html)

pawel_sag August 31, 2013 07:31

problem with blocks
 
5 Attachment(s)
hi,
can someone little help me? how should i change block to get better quality of mesh? thx a lot for advice

cesarcg August 31, 2013 15:16

why don't you give a try to the extrude blocking command?

Far August 31, 2013 15:36

there is some gap between two surfaces in transition region. Also use exturde along curve command.

pawel_sag September 1, 2013 08:41

4 Attachment(s)
ok i will try, but first i will have to learn how to use it. I start using icem few days ago. Thx for help,

it's again me. I can't find any tutorial or information how to use extrude. When i try to use it, i allways get some error..maybe someone know turial or video how to use it.

i try to mesh my profile in 2 diffrent way, but i still get bad element.

FJSJ September 2, 2013 06:12

Hi Pawel,

If you want to create a surface between those two pipes you have to do:

1║ - Create a representative curve of the surface to extrude.

Go to Geometry -> Create/Modify Curve -> Concatenate/Reapproximate Curves and choose the two curves (in Fluid_2 or Fluid_3) to form a circunference.

2║- Create a drive curve.

Go to Geometry -> Create/Modify Curve -> From Points and select one point in Fluid_1 and other point in Fluid_2.

3║- Create extrude surface

Go to Geometry -> Create/Modify Surface -> Curve Driven and select the curve created in third step and circunference created in second step.


aaextrude

pawel_sag September 2, 2013 12:51

1 Attachment(s)
i don't know how to create proper mesh for pipe with shutter.

cesarcg September 2, 2013 12:57

if you don't mind it'd be more helpful that you share the *.tin file.

regards.

pawel_sag September 2, 2013 13:05

1 Attachment(s)
thanks you for all of your help and replies

cesarcg September 3, 2013 15:29

dear pawel,

first of all, i did a little modification of the geometry you provided in order to have a guide curve along the pipe of your model. i added also some points that may serve as reference to the blocking. i suggest you to start with a 3D blocking by selecting appropriate entities and also the desired options, for instance "project vertices and orient with geomtry". to initialize the first block you can select the entities (curves) shown in the picture below

https://dl.dropbox.com/s/q3suv864hde0p69/image1.png

to obtain a block aligned with the corresponding section of the geometry as depicted in the next figure.

https://dl.dropbox.com/s/p0kjaz3ao400htg/image2.png

after this procedure, you'll be able to use the command "extrude along curve" to generate the blocking for the rest of the geometry. please take care of the options "twist per layer" and "number of layers".

i came up with a topology (approach2) in which i obtained the premesh shown in the following picture,

https://dl.dropbox.com/s/u863zsijjscit0h/image3.png

however, using the approach2 the region of the shutter cannot be meshed due the position of this one. it'd be easier to do using the approach1. here are the geometry and blocking files.

regards.
CÚsar

pawel_sag September 4, 2013 05:51

Thanks you helped me a a lot
Now I have a problem with Fluent, any advice for this simulation?
i try using model K-epsilon (Standraed, rng, realizable) and k-omega (sst).
Which algoritm is best ? Simple? or i have to try all of them and find the right one?

cesarcg September 4, 2013 08:12

you still have to deal with the meshing of the shutter.

pawel_sag September 4, 2013 10:00

1 Attachment(s)
now i have something like this, there still bad elements but i will try to fix them

cesarcg September 4, 2013 13:13

i can't see very well the behavior of these bad cells. please show more closer views. are you using o-grid?

pawel_sag September 4, 2013 14:13

1 Attachment(s)
yes i use it, maybe i did something wrong.
i add file with my actual version

cesarcg September 4, 2013 15:43

pawel,

you did the blocking in the wrong way. as i see from your actual version, you're sticked to the pattern of your first topology (i.e., trying to match the blocking with the geometry through horizontal and vertical splits). i also see that you didn't use the "extrude along curve" command since your actual version of the geometry lacks of a curve describing the path of the pipe.

check the blocking files that i provided you and compare them with yours, specially in the region of the twist of the pipe. you'll see the difference in the blocking and behavior of the mesh. also, revise again the above suggestions and pay attention in the part:

Quote:

after this procedure, you'll be able to use the command "extrude along curve" to generate the blocking for the rest of the geometry. please take care of the options "twist per layer" and "number of layers".
regards.


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