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-   -   Turbulence residuals (https://www.cfd-online.com/Forums/star-ccm/73400-turbulence-residuals.html)

Jey March 7, 2010 08:53

Turbulence residuals
 
Hi,

I am running a simple analysis on a flow over a race car.
This is just a preliminary analysis and hence I am using the standard ke turbulence model with default CD ADAPCO parameters.

All my residuals look OK except for Tdr (Turb. Dissipation rate) and Tke (Turb. Kinetic Energy) residuals.

The Tdr and Tke are of 10e-2 order.

Should we be worried about this?
If so, how can we reduce the Tdr and Tke residuals ?

Any advice is much appreciated. Advance Thanks,
Jey

Maddin March 12, 2010 08:41

Look for the monitor. The residuals are normalized.

Vinicius March 17, 2010 09:31

You donīt need to worry about that. These residuals are normalized, so you need to monitor another variables such as pressure, drag force, mass flows... When they stabilize your simulation is converged.

ong khi July 20, 2016 23:10

Quote:

Originally Posted by Vinicius (Post 250435)
You donīt need to worry about that. These residuals are normalized, so you need to monitor another variables such as pressure, drag force, mass flows... When they stabilize your simulation is converged.

Hi, i am struggling with the convergence problems too. If Tke and Tdr are normalized, I can just ignore them? and only concentrating on monitoring the stabilization of other variables?

Thanks in advance!

karahan July 25, 2017 08:14

In my opinion, all of the residuals must decrease at least to the order of 10e-4.

Please correct me if I am wrong.

ashokac7 July 25, 2017 14:49

Quote:

Originally Posted by karahan (Post 658387)
In my opinion, all of the residuals must decrease at least to the order of 10e-4.

Please correct me if I am wrong.

Residual for energy of order of E-7 are considered converged.

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wxs9872002 August 4, 2017 05:48

Maybe try SST K-Omega model.

karahan October 28, 2020 05:11

Quote:

Originally Posted by karahan (Post 658387)
In my opinion, all of the residuals must decrease at least to the order of 10e-4.

Please correct me if I am wrong.

Residuals are normalized with respect to some defined initial iterations. It is not a must, that they decrease a certain order of magnitude. The important thing is, that they become somewhat stable, which meanse that the solution is stable. This is also valid the for other field variables of the flow.


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