Learning Forum

[Naresh]

Hi, I came across this video on youtube, and would like to know more about the mesh such as the internal structure? is there a reason to do it that way?

Am i correct in saying there is an o-grid around the cylinder?

 

Source:https://www.bing.com/videos/riverview/relatedvideo?&q=circular+cylinder+CFD+ansys+icem&&mid=835B3DE4545163852C9F835B3DE4545163852C9F&&FORM=VRDGAR

 

thanks!

[mert.berkman]

Hi Naresh,

 

Yes, you are correct there is an O-grid for that block in ICEMCFD. O-grids are used in ICEM to generated high quality block-structured hexahedral cells to generate mesh in and around circular shapes. 

[Naresh]

Hi Mert, thanks for confirming that. 

for the rest of the topology (the horizontal and vertical lines around the cylinder), is there a name for their structure please? It looks like a H to me so I thought H topology? 

[Rob]

The other name is "butterfly mesh" as the side blocks resemble wings. It's how we meshed things in the "good old days" before unstructured meshes were invented. You'll find the approach in many text books, but if you follow the tutorials it's not something we tend to use in a commercial environment any longer. 

[Naresh]

Hi Rob, thanks for that. I can see why it's called that. 

for the area outside of the butterfly mesh, is there a name for that please? 

[Rob]

I don't think so. The overall mesh may be referred to as multi-block, and in older terms you can see the i, j & k cell alignment (they're equivalent to x, y & z but in a 90 degree bent pipe you'd have i along the pipe, j & k would be across) is maintained. 

In a "modern" mesh I'd probably use a pave mesh with inflation. This allows refinement in the wake and is potentially more efficient in terms of cell count. A lot has changed since Fluent 2.99..... 

[Naresh]

Thanks for clearing that up Rob. Merry Christmas!