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-   -   SU2 Residuals (http://www.cfd-online.com/Forums/su2/112942-su2-residuals.html)

robyTKD February 8, 2013 05:52

SU2 Residuals
 
Hallo,

I am not able to understand how residuals are calculated.
Are they the sum of all residuals in each cell or the maximum value in the computational domain?
And also, are values saved in the history.csv the log10 of the ratio Res/Res_ref, where Res_ref is a reference value, or simply the log10 of the residuals?

Thank you,
Roberto

fpalacios February 15, 2013 21:03

The residual is the L-2 norm of the residual in the entire domain, and then we compute the log10.

My recommendation is to use tecplot (it is possible to obtain an evaluation copy), the paraview output is unsupported.

Cheers,
Francisco

robyTKD February 17, 2013 13:44

Thank you Francisco for the reply.

Cheers,
Roberto.

malik March 15, 2013 08:19

SU2 residuals
 
Hi,

I am running Inviscid ONERA M6 mesh using the SU2 code. I have run it but it stops after 193 iterations, iwant to increase the number of iterations to to 1500 so plz can you tell what i have to change in cfg file.

Thanks in advance

Regards,
Malik

samiam1000 March 15, 2013 08:36

Hi Malik,

this is the entry to change the max number of iterations
Code:

% Number of total iterations
EXT_ITER= 99999999999

Nevertheless, if it exits after 193 steps it is probably due to a convergence criteria.

Please, post your config file.

malik March 15, 2013 17:56

SU2 residuals
 
Hi samiam,
there is no error, i need to change convergence criteria

thanks

robyTKD June 17, 2013 07:51

Hi,

I have other questions regarding residuals.

1. Where can I find the strings of the code where residuals are computed?
2. Is it possible to save residuals in the output file? I need to know at least the infinite-norm of residuals.
3. When running SU2_CFD, it prints "Maximum residual: -3.8985e+00, located at point 49659."; I think it is the maximum Res(rho) in the domain, is it right?

Cheers,
Roberto

OVS March 31, 2016 21:55

I'm sorry but your answer about the residuals is not clear to me. I get you use the RMS norm on the residuals, but I'm still wondering about the second question from Roberto:

Quote:

Originally Posted by robyTKD (Post 406693)

are values saved in the history.csv the log10 of the ratio Res/Res_ref, where Res_ref is a reference value, or simply the log10 of the residuals?

Roberto

in other words, are the calculated residuals relative or absolute?

(My guess is they are absolute since you only mentioned the L-2 norm... but I need to ask).

Thanks,
Oliver

tsevine April 5, 2016 18:46

Quote:

Originally Posted by robyTKD (Post 434427)
Hi,

I have other questions regarding residuals.

1. Where can I find the strings of the code where residuals are computed?
2. Is it possible to save residuals in the output file? I need to know at least the infinite-norm of residuals.
3. When running SU2_CFD, it prints "Maximum residual: -3.8985e+00, located at point 49659."; I think it is the maximum Res(rho) in the domain, is it right?

Cheers,
Roberto

Hi Roberto,

for your 3rd question, as far as i know you are right, it is res(rho).

Regards,
Tansu


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