While I have been running some large sims in my quest to create a meaningful Mesh Independence Study for my own project, I have been working with the project geometry of this topic so that I can get a better handle on the nuances of layering to a yPlus of < 1. I am so close to having an 85 million …

NOTE: This is an example procedure to show how I was able to layer a particularly difficult layering requirement. It is not a way to fix all layering issues. However, I do believe the methods I present here can be used to solve a lot of layering problems that you may be having. The parameter val…

[image] 1318980: there is a large size gradient in some areas, might cause some instability but we shall see if the numerics can handle it. I assume you mean the refinement level gradient as you move away from the surface. I chose to only do a surface refinement, to check the robustness of m…

Nice one Dale! Good results! Thanks for sharing. Best, Darren

And a 0-0.15 mapping: [0-p15map]

Nice, would love to find out how to stop those layers cancelling on the trailing edge… if your up for a challenge :wink: Best, Darren

Don’t think it is possible. 15 layers takes a while to inflate from deflated. Any angular edge feature will cause a deflation at it. Just the way Snappy layers I think. That lonely red deflation on the root rib is caused by a single face on the symmetry surface that Snappy decided is part of the…

Yer, I was just thinking since we have made good progress documenting how to make layering more robust by altering the layering controls maybe there was a setting that controls this deflation. But your right I presume not since we haven’t found it yet.

Yep, you never know, it may be possible, I can’t tell you how many hours it took me just to get a small handle on even one layering parameter that does not do what you expect it to do by thinking what the name means. The brute force method is not easy and eats up core hours too :wink:

@DaleKramer This is typical snappyhexmesh. It is not easy to generate prism layers that has y+<1 while maintaining a good coverage. On a side note, RANS does not require y+<1. A max y+=1 is enough. In reality, a max y+~5 is also acceptable on a large scale industrial mesh. This is because 0<y+<5 i…

Hi Dale, I’m looking at this after you shared on my post. Why do u say 101k cells disappeared? I see that this number is about negative volume, concavity etc… the number for min determinant is also much smaller? Could you help me by explaining your conclusion further? Weisheng

@cweisheng When I say ‘disappeared’, I mean that they were considered by Snappy to not meet the quality criteria that is set in your requested meshing parameters since, first of all Snappy begins by creating 100% of the layers you requested and then starts removing cells in the layered zone if they…

SimScale CAE Forum

Layering for yPlus of less than 1

Using SimScale

DaleKramer March 9, 2019, 10:28am 19

WOW, I only had to see this and I was convinced:

Not wanting to take over your suggestion but I have created one of my polls for this

3 Likes