|
[Sponsors] |
March 7, 2016, 10:44 |
Production TKE in LES
|
#1 |
Senior Member
Cees Haringa
Join Date: May 2013
Location: Delft
Posts: 607
Rep Power: 0 |
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 |
|
March 8, 2016, 02:10 |
|
#2 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,754
Rep Power: 66 |
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. |
|
March 8, 2016, 03:38 |
|
#3 |
Senior Member
Cees Haringa
Join Date: May 2013
Location: Delft
Posts: 607
Rep Power: 0 |
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?). |
|
|
|
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 |