BC's for komega SST (low / hi Re setups)
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hi everyone,
i have been testing my komega SST setup for OF using a simple flat plate geometry, and BC's i have worked out from looking at a number of other posts on the issue. although there is a *lot* out there on the setups you need to use, i dont seem to get the impression that there has been widespread agreement on how the model is supposed to be implemented :D anyway, so i have a low Re and a hi Re mesh. the BC's for the two meshes are: For the hi Re mesh: Code:
'k' Code:
'k' Using yPlusRAS to check the meshes, i see that the first node points for each mesh are in the correct region, so i cant quite work out what the problem is. BC's perhaps?? anyway, i would appreciate any feedback on anything obvious i have gotten wrong + am quite keen to 'finalise' the 'proper' approach for the current implementation of komega SST (OF v2.1.1) thanks a lot in advance! Jonathan 
never mind ... solved it ...

Hi Jonathan,
How did you resolve this? 
Hi Jonathan,
what formula do you use to set 'value uniform 1e9' for k at the wall for your low Reynolds mesh (y+~1) ? Best regards, Stephane. 
Hi Stephane,
I didnt use a formula  looking through the forums and theory, i realise that omega tends to infinity at the wall  therefore, i just used a large number as the omega BC ... regards jonathan 
Hi Jonathan
I also did this validation with komega SST turbulence model. But with Low Re and high Re model both failed. There is mismatch in the loglaw region. Can you please give a hint how you solve it? Best regards, Ye 
hi Kid,
I havent looked at OF for a little while, but in the last version i was using (2.1.1), i finally used the following for a low Re mesh: 'k' > set to SMALL no at wall 'omega' > use omegaBC built into OF. This calculates omega at the wall using the correct formula from Menter 'nut' > I used 'calculated' condition and not nut wall function as in my first post PS I didnt do anymore with the hiRe meshes, as my project needed lowRe only. hope this helps a little. cheers jonathan PPS I dont know what the latest versions of OF are using for turbulence wall BC's these days. Might pay to download the latest UG and look through the release notes and code to see what is actually going on ... :) cheers jon Quote:

Hi Jonathan,
Thanks a lot for your reply. I finally got the correct result after several trying. Best regards, Ye 
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