Laminar or Turbulent simulation

rajnarayang · October 3, 2016, 13:32

Hi All,

I am simulating laminar flow (Reynolds number of 500) in a channel with square and rectangular protrusions inside. From experimental studies conducted, it "seems" that flow turns turbulent. Should I simulate the flow as Turbulent flow and use SST model or laminar flow or use transition models?

Please let me know your thoughts.

FMDenaro · October 3, 2016, 14:06

it depends on the problem..if you have transition along the channel, that is the flow in inlet is laminar and then becomes turbulent, you have to use DNS or LES.

rajnarayang · October 3, 2016, 14:15

Thanks for your reply. I am trying to perform optimization and hence have to run multiple cases. Hence running a computationally intensive LES or DNS doesn't sound like a good option for me right now. I was wondering if any RANS options may be available.

malv83 · October 13, 2016, 12:25

One of the best options for RANS transition simulations is he NEW k-omega-v2 model:

Maurin Lopez. D. K. Walters. “Prediction of transitional and fully turbulent free shear flows using an alternative to the laminar kinetic energy approach”. Journal of Turbulence, Vol 17, Iss. 3, 2016.

https://www.researchgate.net/publica...nergy_approach

This new model is an improvement (in theory and results) to the popular k-kl-omega model. Therefore the k-omega-v2 model is a reliable and robust model for transitional flows (see the paper).

October 3, 2016, 13:32	Laminar or Turbulent simulation	#1
rajnarayang New Member Raj Narayan.G Join Date: Nov 2011 Location: USA Posts: 17 Rep Power: 14	Hi All, I am simulating laminar flow (Reynolds number of 500) in a channel with square and rectangular protrusions inside. From experimental studies conducted, it "seems" that flow turns turbulent. Should I simulate the flow as Turbulent flow and use SST model or laminar flow or use transition models? Please let me know your thoughts.

October 13, 2016, 12:25	Transition RANS model	#4
malv83 Member Alberto Join Date: Sep 2013 Posts: 37 Rep Power: 12	One of the best options for RANS transition simulations is he NEW k-omega-v2 model: Maurin Lopez. D. K. Walters. “Prediction of transitional and fully turbulent free shear flows using an alternative to the laminar kinetic energy approach”. Journal of Turbulence, Vol 17, Iss. 3, 2016. https://www.researchgate.net/publica...nergy_approach This new model is an improvement (in theory and results) to the popular k-kl-omega model. Therefore the k-omega-v2 model is a reliable and robust model for transitional flows (see the paper).

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October 3, 2016, 14:06		#2
FMDenaro Senior Member Filippo Maria Denaro Join Date: Jul 2010 Posts: 6,768 Rep Power: 71	it depends on the problem..if you have transition along the channel, that is the flow in inlet is laminar and then becomes turbulent, you have to use DNS or LES.

October 3, 2016, 14:15		#3
rajnarayang New Member Raj Narayan.G Join Date: Nov 2011 Location: USA Posts: 17 Rep Power: 14	Thanks for your reply. I am trying to perform optimization and hence have to run multiple cases. Hence running a computationally intensive LES or DNS doesn't sound like a good option for me right now. I was wondering if any RANS options may be available.