LES and TKE calculations

MST · August 3, 2013, 22:38

Hi Everyone,
I have some questions. I am running LES WALE simulation in CFX. I got the following variables for the velocities as outputs:
1. Statistical Reynolds Stress uu
2. Statistical Reynolds Stress uv
3. Statistical Reynolds Stress uw
4. Statistical Reynolds Stress vv
5. Statistical Reynolds Stress vw
6. Statistical Reynolds Stress ww
7. Velocity Correlation uu
8. Velocity Correlation uu.Trnavg
9. Velocity Correlation uv
10. Velocity Correlation uv.Trnavg
11. Velocity Correlation uw
12. Velocity Correlation uw.Trnavg
13. Velocity Correlation vv
14. Velocity Correlation uw.Trnavg
15. Velocity Correlation vv
16. Velocity Correlation vv.Trnavg
17. Velocity Correlation uw
18. Velocity Correlation vw.Trnavg
19. Velocity Correlation ww
20. Velocity Correlation ww.Trnavg
21. Velocity
22. Velocity.Trnavg
23. Velocity x
24. Velocity.Trnavg x
25. Velocity y
26. Velocity.Trnavg y
27. Velocity z
28. Velocity.Trnavg z

V (full field , instantaneous) = resolved Velocity+ unresolved (V’).

1- Does the Velocity # 21 above represent full field velocity and (Velocity.Trnavg # 22) represent resolved part? If so, unresolved (V’)= Velocity- Velocity.Trnavg)? is V’ represent rms velocity?
2- Is “Statistical Reynolds Stress” represent unresolved part and can I calculate rms V’ by taking square-root of Statistical Reynolds Stress variable? If so, what is the difference between V’ that was calculated in question 1 and V’ from Statistical Reynolds Stress?
3- To calculate the mean flow kinetic energy, is it correct to use Kmean =0.5(Velocity Correlation uu.Trnavg+ Velocity Correlation uvv.Trnavg+ Velocity Correlation ww.Trnavg).
4- How to calculate the turbulent kinetic energy from the contribution of both resolved and unresolved parts, Kt= Kres+Kmod ?
5- What is the good metric for presenting turbulence strength? Turbulence eddy viscosity ratio or TKE?
Thank you so much in advance,,,

MST · August 7, 2013, 18:57

No body wants to share any knowledge about this?!!

FMDenaro · August 8, 2013, 03:51

Quote:

Originally Posted by MST

No body wants to share any knowledge about this?!!

Sorry but I think your question is for experts in CFX

Mazze[ITA] · May 30, 2016, 06:26

Did you find an answer?

August 3, 2013, 22:38	LES and TKE calculations	#1
MST New Member Join Date: Dec 2010 Posts: 6 Rep Power: 15	Hi Everyone, I have some questions. I am running LES WALE simulation in CFX. I got the following variables for the velocities as outputs: 1. Statistical Reynolds Stress uu 2. Statistical Reynolds Stress uv 3. Statistical Reynolds Stress uw 4. Statistical Reynolds Stress vv 5. Statistical Reynolds Stress vw 6. Statistical Reynolds Stress ww 7. Velocity Correlation uu 8. Velocity Correlation uu.Trnavg 9. Velocity Correlation uv 10. Velocity Correlation uv.Trnavg 11. Velocity Correlation uw 12. Velocity Correlation uw.Trnavg 13. Velocity Correlation vv 14. Velocity Correlation uw.Trnavg 15. Velocity Correlation vv 16. Velocity Correlation vv.Trnavg 17. Velocity Correlation uw 18. Velocity Correlation vw.Trnavg 19. Velocity Correlation ww 20. Velocity Correlation ww.Trnavg 21. Velocity 22. Velocity.Trnavg 23. Velocity x 24. Velocity.Trnavg x 25. Velocity y 26. Velocity.Trnavg y 27. Velocity z 28. Velocity.Trnavg z V (full field , instantaneous) = resolved Velocity+ unresolved (V’). 1- Does the Velocity # 21 above represent full field velocity and (Velocity.Trnavg # 22) represent resolved part? If so, unresolved (V’)= Velocity- Velocity.Trnavg)? is V’ represent rms velocity? 2- Is “Statistical Reynolds Stress” represent unresolved part and can I calculate rms V’ by taking square-root of Statistical Reynolds Stress variable? If so, what is the difference between V’ that was calculated in question 1 and V’ from Statistical Reynolds Stress? 3- To calculate the mean flow kinetic energy, is it correct to use Kmean =0.5(Velocity Correlation uu.Trnavg+ Velocity Correlation uvv.Trnavg+ Velocity Correlation ww.Trnavg). 4- How to calculate the turbulent kinetic energy from the contribution of both resolved and unresolved parts, Kt= Kres+Kmod ? 5- What is the good metric for presenting turbulence strength? Turbulence eddy viscosity ratio or TKE? Thank you so much in advance,,, Mazze[ITA] likes this.

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August 7, 2013, 18:57		#2
MST New Member Join Date: Dec 2010 Posts: 6 Rep Power: 15	No body wants to share any knowledge about this?!!

May 30, 2016, 06:26		#4
Mazze[ITA] Member Lorenzo Mazzei Join Date: Dec 2010 Posts: 60 Rep Power: 15	Did you find an answer?