Mesh inflation layer not shown


#1

Hi all,

I am currently trying to inflate boundary layer of 1st layer < 1e-5. When I try to make the inflation layer smaller, the layer did not grow. I tried using both relative and absolute size and also played with the advance options. Can you give me some feedback on what I did wrong?

From the mesh log, I can see that the inflation layer is as intended and after “Selecting externalDisplacementMeshMover displacementMedialAxis” there is some iteration that causes the layer not to grow.

This is the link to my project
https://www.simscale.com/workbench/?pid=3258566015299778947#tab_0-0

When I am post-processing, there is line in my mesh. Is it common?

Any feedback from will be greatly appreciated.

Thanks


#2

Hi @ksum!

Tagging my colleagues (@PowerUsers_CFD) here who might help you out here.

Cheers and all the best!

Jousef


#3

Hi everyone,

Struggling with this issue for my meshes and BL inflation as well. Talked to ksum over this but its quite difficult to pinpoint the issue. However a quick search of the issues brought up some possible problems that I thought I’d share.

For BL inflation, it seems like the layer is inflated, but the mesh’s quality control just deletes off the layer due to how skewed the inflation is. Relaxing the quality control isn’t an ideal solution as the result will be a BL sure, but not within the required quality. So a little stuck on this and Ksum’s comment on the movement of the medial axis might actually be causing this issue. Would love to hear anyone’s thoughts on this.

As for the random grid lines as seen, these still perplex me and I continue to run into this meshing problem. While initial probing of the results show that such anomalies don’t seem to affect the results significantly, I would prefer to get the mesh “perfect” and eliminate something like this. Again, no idea why this is showing up.

Hope to hear a solution soon!

Cheers.

Regards,
Barry


#4

Hey guys,

will reach out to one of my colleagues from the CFD team! We will keep you up-to-date!

All the best!

Jousef


#5

Hi @ksum, how small do you want the layers?

I have a project here that takes the outer layer (largest) to 0.1mm (absolute sizing)
https://www.simscale.com/projects/1318980/trying_layer_inflation/

Let me know if it doesn’t help and I could try to make it smaller.

Kind regards,
Darren


#6

Hi @1318980

For my Y+ value to be less than 1, I need a first layer thickness of 1e-5 or below with 10 - 15 layers.

Thanks


#7

The same project link has the values you need however you might want to play with the quality as some of the layer is cancelled.

Hope this helps,
Darren


#8

Hey @1318980

Thanks for the help. I would try to improve the quality.

What is causing the inflation layer not to appear? Is it the refinement is not enough or the Max face aspect ratio for layers and Max ratio of layer thickness to medial length?

Thanks!


#10

Hi @ksum,

I found minimum volume ratio to neighbouring cell helped, This is because the difference in volume between the final layer cell and the next cell was quite a lot, however, by reducing the number we can allow this.

Hope this helps,
Darren