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-   -   Convergance !!!!!!!!!!! (https://www.cfd-online.com/Forums/cfx/22649-convergance.html)

Neser June 3, 2006 21:51

Convergance !!!!!!!!!!!
 
in spray particles tracking process, I got the following CFX solver results

1- U-Mom RMS Res 4.8E-03

U-Mom Max Res 8.8E-02

V-Mom RMS Res 4.7E-03

V-Mom Max Res 8.8E-02

W-Mom RMS Res 2.1E-02

W-Mom Max Res 5.8E-01

P-Mass RMS Res 6.5E-05

P-Mass Max Res 4.7E-03

U-Mom Domain Imbalance, in %: 0.0110 % V-Mom Domain Imbalance, in %: -0.0010 % W-Mom Domain Imbalance, in %: 1.7424 % P-Mass Domain Imbalance, in %: -0.0283 %

Is the could be convergant results

regards


Michael June 4, 2006 21:32

Re: Convergance !!!!!!!!!!!
 
fairly high W-mom imbalance. plus those RMS values are high IMO. I wouldn't trust the solution how was the residual trace? oscillating can be a function of the grid resolution and also the model selected. what models are you using? how is your grid in the are of the max residuals? is it a coarse grid (grid topology would be nice) in this area and is there a large velocity gradient or recirculation in this area?

in our work, if we are having problems converging we require two orders or magnitude difference between the RMS and MAX residuals, then we look where those max residuals are located.

Neser25 June 6, 2006 08:36

Re: Convergance !!!!!!!!!!!
 
Thank you for your reply, about your questions:

1. I am using particle tracking model. Therefore, as far as I know, mesh size has not a great effect.

2. particle injection downward speed is about 8 m/s, however, the upword hot air spped is 0.1 m/s)

3. I do not know how I can get the place which has max residuals.

Regards



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