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-   -   Overestimation of velocity profile in turbulent channel flow (https://www.cfd-online.com/Forums/main/220509-overestimation-velocity-profile-turbulent-channel-flow.html)

Cnl5 September 10, 2019 02:55

Overestimation of velocity profile in turbulent channel flow
 
Dear all,

Currently, I am using wall-resolving implicit large eddy simulation to simulate turbulent channel flow. The channel is periodic in streamwise and spanwise direction while a non-slip condition is applied at the bottom wall. The calculated y+ is below 1. However, the velocity profile from the LES is overestimated in log-region as compared to that of Spalding. Does anyone face this problem before?:confused:

https://imgur.com/a/Z2QD083

https://imgur.com/a/Z2QD083

FMDenaro September 10, 2019 03:31

Quote:

Originally Posted by Cnl5 (Post 744309)
Dear all,

Currently, I am using wall-resolving implicit large eddy simulation to simulate turbulent channel flow. The channel is periodic in streamwise and spanwise direction while a non-slip condition is applied at the bottom wall. The calculated y+ is below 1. However, the velocity profile from the LES is overestimated in log-region as compared to that of Spalding. Does anyone face this problem before?:confused:

https://imgur.com/a/Z2QD084

https://imgur.com/a/Z2QD084




Overestimation of the LES velocity profile is often reported. Have a look here https://www.researchgate.net/publica...mulation_codes


However, you profile in the centerline shows a wrong behavior and I think that something is not correct. Have you waited enough time to let the fields correlating physically from the initial conditions? Check the total kinetic energy in time. How many samples have you used for the statistical averaging?

Avr.Tomer September 19, 2019 22:46

Les
 
Quote:

Originally Posted by FMDenaro (Post 744320)
Overestimation of the LES velocity profile is often reported. Have a look here https://www.researchgate.net/publica...mulation_codes


However, you profile in the centerline shows a wrong behavior and I think that something is not correct. Have you waited enough time to let the fields correlating physically from the initial conditions? Check the total kinetic energy in time. How many samples have you used for the statistical averaging?

Awesome reply and ref! I have a few months of LES ahead of me. Thanks Prof. Denaro!

FMDenaro September 20, 2019 03:15

Quote:

Originally Posted by Avr.Tomer (Post 745063)
Awesome reply and ref! I have a few months of LES ahead of me. Thanks Prof. Denaro!


Hello,
this overestimation effect has been observed using several discretizations and, somehow strangely, often does not appear in the no-model LES.


You can have also a look to this paper https://www.cambridge.org/core/journ...9AE603FD6BB11B


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