Transitional flow (Gamma Theta model)

sharif88 · March 5, 2014, 12:31

Hello everyone
I had a question regarding transitional turbulence option and particularly the Gamma Theta model,
for flow inside a pipe is it possible to treat the flow near the walls as turbulent and in the middle portion as laminar with a transition region in between for the entire pipe length,
from the description of transitional flow I concluded this but I am not sure if it is correct,
Thanks

ghorrocks · March 5, 2014, 16:37

This is exactly what the transitional turbulence model does. The only caveat is that the Gamma Theta model was developed for external flow especially on airfoils, so you have to be careful applying to internal flows. But give it a go and just do a careful validation... which you were going to do anyway, right?

sharif88 · March 6, 2014, 10:16

ghorrocks
Yes of course I validate the results,
So far I am getting good results although I found this method extremely sensitive to IC. and BC.s but after trying a few different settings I got good results
Thanks

ghorrocks · March 6, 2014, 15:59

That is good to hear - and I am not surprised it is sensitive to IC and BCs. Good to hear you have checked this.

March 5, 2014, 12:31	Transitional flow (Gamma Theta model)	#1
sharif88 New Member Majid Join Date: Jan 2014 Location: Canada Posts: 23 Rep Power: 12	Hello everyone I had a question regarding transitional turbulence option and particularly the Gamma Theta model, for flow inside a pipe is it possible to treat the flow near the walls as turbulent and in the middle portion as laminar with a transition region in between for the entire pipe length, from the description of transitional flow I concluded this but I am not sure if it is correct, Thanks

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March 5, 2014, 16:37		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	This is exactly what the transitional turbulence model does. The only caveat is that the Gamma Theta model was developed for external flow especially on airfoils, so you have to be careful applying to internal flows. But give it a go and just do a careful validation... which you were going to do anyway, right?

March 6, 2014, 10:16		#3
sharif88 New Member Majid Join Date: Jan 2014 Location: Canada Posts: 23 Rep Power: 12	ghorrocks Yes of course I validate the results, So far I am getting good results although I found this method extremely sensitive to IC. and BC.s but after trying a few different settings I got good results Thanks

March 6, 2014, 15:59		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	That is good to hear - and I am not surprised it is sensitive to IC and BCs. Good to hear you have checked this.