[Autonomic]

Hi

I'm new to CFD and I'm trying to mesh a tube geometry with a cross section of 500 square micrometres and a length of 30 cm.

I started with a tube of only 0.1cm length just to test the settings with and with the physics preference set to CFD and the automatic method, the mesh generated was quite nice:

http://i.imgur.com/YJ9cEMB.jpg

I then tried the full 30cm length tube using the same settings, but the mesh is much lower quality:

http://i.imgur.com/o6RJsy9.jpg

I have only a limited understanding of ANSYS of meshing techniques but I assumed that increasing the length of the model wouldn't reduce the quality so much.

I'd love to know which settings I need to change in order to get a mesh similar to that of the smaller length tube. If any more information is needed please let me know.

Thanks

[Joyce]

Hi!
Have you solved this problem? I have the same one as your.
THX

[Antanas]

Originally Posted by Joyce

Hi!
Have you solved this problem? I have the same one as your.
THX

What's the problem?

[Autonomic]

It's been a while but I believe I solved it by applying a sweep mesh as well as face sizing with an appropriate element size. In this case of it was 50 micro meters.

[Joyce]

Hi, thanks for response.
I used the sweep method in ANSYS Meshing, and I can get the mesh like this:

Now I want to reduce the element number, that I increase the element size along the length direction, but the element quality reduced and it becomes too low to use.

So do you know how to deal with it? or should I change to use other meshing software like ICEM?
Thank you.

[sarangdalne]

Define a sweep method on that body keep your element size as before (where you were getting a good mesh) and increase the number of sweep divisions to what you want. This will help your mesh quality.

[Antanas]

Originally Posted by Joyce

Hi, thanks for response.
I used the sweep method in ANSYS Meshing, and I can get the mesh like this:

Now I want to reduce the element number, that I increase the element size along the length direction, but the element quality reduced and it becomes too low to use.

So do you know how to deal with it? or should I change to use other meshing software like ICEM?
Thank you.

What quality metric are you talking about?

[Joyce]

Originally Posted by Antanas

What quality metric are you talking about?

I used the 'element quality'.

[Antanas]

Originally Posted by Joyce

I used the 'element quality'.

Not relevant for CFD. You should check Aspect Ratio, Skewness, Ortho. Quality.

[Joyce]

Originally Posted by Antanas

Not relevant for CFD. You should check Aspect Ratio, Skewness, Ortho. Quality.

Thank you for your reply!