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-   -   CFX v12 adding reattachment modification to sst model (http://www.cfd-online.com/Forums/cfx/88302-cfx-v12-adding-reattachment-modification-sst-model.html)

ovechkin May 13, 2011 05:18

CFX v12 adding reattachment modification to sst model
 
Hello,

I need to add the reattachment modification to the Shear Stress Transport model, but Im not sure how to do it. I assume i need to add some lines in the definition file..
can someone give me a clue how to do this?

thanks a lot,
ovechkin

ovechkin May 13, 2011 06:56

..got it. just add "SST Reattachment Modification = On" to Turbulence Model in Command Editor..

cfd_newbie May 13, 2011 06:59

Quote:

Originally Posted by ovechkin (Post 307510)
..got it. just add "SST Reattachment Modification = On" to Turbulence Model in Command Editor..

Hi,
Do you know what is the SST Reattachment Modification how is it different from the standard SST ? Why and where is it used. Can you share some references ?

ghorrocks May 13, 2011 07:08

I am not familiar with the reattachment model. In fact I did not even know it was in there. Do you know any details about it, or have any documentation on it?

ovechkin May 13, 2011 07:45

Unfortunately I don't have any references/documentation on it. All I know is that the Reattachment Model accounts for an additional production of kinetic energy in seperated shear layers.
We use it for simulation of a turbulent premixed combustion process

Far June 27, 2011 15:50

It is basically related to fact that the baseline SST (original SST) predicts the larger separation bubble than the experimental values. This is due to the wrong prediction of reattachment point (boundary layer attachment at further downstream location). Therefore the RM modification was introduced in production term to account for the realistic separation bubble length and hence earlier attachment. It is to be noted that this limiter is not activated in the attached flow and hence base line sst is fully recovered.

Keeping in view above discussion, base line SST model has difficulties in predicting the stall point correctly and simulation often stops due to premature numerical stall.


Best Regards
Far

swm March 4, 2014 04:59

Quote:

Originally Posted by ovechkin (Post 307510)
..got it. just add "SST Reattachment Modification = On" to Turbulence Model in Command Editor..

In version 14.5,it seems that it is NOT allowed to add this to TURBULENCE MODEL?


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