How can TKE help me in explaining flow separation happening in an airfoil?

yujin_cfd · July 20, 2024, 02:18

Hi all,
I am doing URANS simulation to study the effect of turbulence intensity on NACA 2414 airfoil at a Re of 100000. The lift coefficients increase with the increase in TI for an AOA of 20 deg, and the drag coefficients decrease with an increase in TI. How can the TKE plots be used to explain flow separation and variation in aerodynamic coefficients?
I am adding TKE plots at 20 deg AOA.

LuckyTran · July 20, 2024, 12:00

I think it is meaningless to discuss physical explanations when you have a discontinuity in your tke plots caused by the grid! How can you explain a change in the tke when you didn't change the tke?

yujin_cfd · July 21, 2024, 07:18

Thanks for the reply.
Consider me a beginner. I have 2 questions on your reply.
1. What do you mean by discontinuity caused by the grid? If I take it into CFD Post, I am still able to get a continuous contour for the TKE.
2. Changing the Turbulence Intensity basically changes the TKE for the flow as well right? Can I assume that high TKE is associated with flow separation and dissipation?

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July 20, 2024, 12:00		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,743 Rep Power: 66	I think it is meaningless to discuss physical explanations when you have a discontinuity in your tke plots caused by the grid! How can you explain a change in the tke when you didn't change the tke?

July 21, 2024, 07:18		#3
yujin_cfd New Member Anupam Krishnan Join Date: Nov 2020 Posts: 4 Rep Power: 5	Thanks for the reply. Consider me a beginner. I have 2 questions on your reply. 1. What do you mean by discontinuity caused by the grid? If I take it into CFD Post, I am still able to get a continuous contour for the TKE. 2. Changing the Turbulence Intensity basically changes the TKE for the flow as well right? Can I assume that high TKE is associated with flow separation and dissipation?