wall Shear stress understimation from LES

moh-farmani · November 30, 2016, 12:35

I have done some RANS simulations with S-A model of turbulent flow over a 30cm chord flat plate in O.F.3.0.1 and validated U+-Y+ with some DNS data.I have used a block shaped step with 1mm high for generating turbulent flow. As i have run LES simulation of the flow, wall Shear Stress is underestimated about 50%

. I have tried all LES model and generated some fine mesh for high resolution wall-resolved LES, but results are frustrating. could someone please help me on the topic?
any guide is appreciated.

Regards
mohammad

nimasam · December 2, 2016, 03:40

what is the average y+ value for LES simulation?

moh-farmani · December 2, 2016, 09:44

Hi Nima
thanks for your reply. the average of y+ is 0.6.

moh-farmani · December 2, 2016, 09:52

Hi Nima
The average value for y+ in the LES simulation is 0.6 after 10FTT.

moh-farmani · December 2, 2016, 09:55

All Foamers
could anyone have some experiences of the thread.I appreciate any help.

Regards

November 30, 2016, 12:35	wall Shear stress understimation from LES	#1
moh-farmani New Member mohafarmani Join Date: Aug 2015 Location: shiraz Posts: 14 Rep Power: 10	I have done some RANS simulations with S-A model of turbulent flow over a 30cm chord flat plate in O.F.3.0.1 and validated U+-Y+ with some DNS data.I have used a block shaped step with 1mm high for generating turbulent flow. As i have run LES simulation of the flow, wall Shear Stress is underestimated about 50%. I have tried all LES model and generated some fine mesh for high resolution wall-resolved LES, but results are frustrating. could someone please help me on the topic? any guide is appreciated. Regards mohammad

December 2, 2016, 03:40		#2
nimasam Senior Member Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,266 Blog Entries: 1 Rep Power: 24	what is the average y+ value for LES simulation? __________________ My Personal Website (http://nimasamkhaniani.ir/) Telegram channel (https://t.me/cfd_foam)

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December 2, 2016, 09:44		#3
moh-farmani New Member mohafarmani Join Date: Aug 2015 Location: shiraz Posts: 14 Rep Power: 10	Hi Nima thanks for your reply. the average of y+ is 0.6.

December 2, 2016, 09:52		#4
moh-farmani New Member mohafarmani Join Date: Aug 2015 Location: shiraz Posts: 14 Rep Power: 10	Hi Nima The average value for y+ in the LES simulation is 0.6 after 10FTT.

December 2, 2016, 09:55		#5
moh-farmani New Member mohafarmani Join Date: Aug 2015 Location: shiraz Posts: 14 Rep Power: 10	All Foamers could anyone have some experiences of the thread.I appreciate any help. Regards