[Getdp] ... non-linear iteration convergence ...

Matt Koch mattkoch at scitex.us
Wed Sep 30 22:01:54 CEST 2009


Hello Bernhard,

yes, I think that is exactly what I did now, and it works like a charm! 
Thanks for your help, and for paving the way to solving this problem by 
putting up your FaceConduct2D example up on the Wiki! I have put my 
RadiativeHeatTransfer example up on the Wiki as well just now.

Best Regards,

Matt


Kubicek Bernhard wrote:
> What is done in commercial CFD sometimes is that one splits the T^4 like that: T^3*T
> The T^3 is taken constant for each matrix, while the T is included linear in the system matrix.
> Maybe there is a way of doing that in getdp...
>
> Also, a good initial guess can help a lot...
>
> greetings, bernhard
> -----------------------------------
> Bernhard Kubicek
> Energy Department
> Electric Energy Systems
>
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> ________________________________________
> From: getdp-bounces at ace20.montefiore.ulg.ac.be [getdp-bounces at ace20.montefiore.ulg.ac.be] On Behalf Of Matt Koch [mattkoch at scitex.us]
> Sent: Tuesday, September 29, 2009 12:59 AM
> To: getdp at geuz.org
> Subject: [Getdp] ... non-linear iteration convergence ...
>
> Hello All,
>
> I have made some progress on my radiative heat exchange problem from a
> long time ago. This is true radiative heat exchange with configuration
> factors, not just a simple T^4 boundary condition. However, I am facing
> convergence problems in my non-linear iteration and have to go to
> relaxation factors as small as 0.01 and smaller in order to make things
> move, and even then it often fails to converge. Does anyone have any
> advice on such an issue? Are there other approaches to solving a
> non-linear problem in GetDP, i.e. other than "IterativeLoop[ItnCnt,
> ItnErr, ItnRlx]"? For example, I stumbled across a JacNL notation
> somewhere, but have no idea how to set this up?Any thoughts would be
> much appreciated.
>
> Thanks,
>
> Matt Koch, Ph.D., P.E.
> Science & Technology Consultants (SciTeX)
> www.scitex.us
> mattkoch at scitex.us
> (830)-249-9499 (o)
> (830)-446-1839 (c)
>
>   

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