CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Production TKE in LES

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 7, 2016, 10:44
Default Production TKE in LES
  #1
Senior Member
 
Cees Haringa
Join Date: May 2013
Location: Delft
Posts: 607
Rep Power: 0
CeesH is on a distinguished road
Dear all,

I am currently running a large eddy simulation (so far I have only experience with RANS), and I am noticing a significant underestimation of the turbulence dissipation rate.

It was adviced I'd check the energy budget, i.e. are dissipation and production in balance. But I am a bit lost on how to do this check. How can I calculate the turbulent kinetic energy production from FLUENT?

Thanks in advance!
Cees
CeesH is offline   Reply With Quote

Old   March 8, 2016, 02:10
Default
  #2
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,654
Rep Power: 65
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
In the RANS sense (4th term on RHS):
https://en.wikipedia.org/wiki/Turbulence_kinetic_energy

To do it in the instantaneous sense is a bit tricky because of the spatial filtering in LES. You have to keep track of the filtered velocities and the influence of the SGS.
LuckyTran is offline   Reply With Quote

Old   March 8, 2016, 03:38
Default
  #3
Senior Member
 
Cees Haringa
Join Date: May 2013
Location: Delft
Posts: 607
Rep Power: 0
CeesH is on a distinguished road
I was afraid it wouldn't be that straightforward.

Anyway, my problem is that energy dissipation is significantly underestimated compared to experiments (and RANS). So I wanted to check whether production and dissipation balance. Do you think the RANS-sense implementation can answer that? (or perhaps, do you see a more straightforward way to do the budget check? I haven't gotten around to learning all the ins and outs on LES yet. For example, is the notion that <k_t> seems to be constant in time sufficient to declare the budget closes?).
CeesH is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Howto get the production and dissipation of TKE?? lakeat OpenFOAM Running, Solving & CFD 9 March 22, 2022 12:14
LES and TKE calculations MST Main CFD Forum 3 May 30, 2016 07:26
TKE budget equation in LES doctorWho Main CFD Forum 3 March 12, 2014 12:27
Subgrid TKE in LES saqure FLUENT 0 February 12, 2011 22:42
How to calculation TKE in LES lizzy0zhou Main CFD Forum 4 February 11, 2011 14:05


All times are GMT -4. The time now is 04:31.