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Why do we care about how much residual drops from the initial condition? |
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April 8, 2014, 05:29 |
Why do we care about how much residual drops from the initial condition?
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#1 |
Senior Member
Meimei Wang
Join Date: Jul 2012
Posts: 494
Rep Power: 15 |
Hi,
I know that the residual value is the way to quantify and judge whether the simulation has converged or not. So I always use this value and look it as an important criteria to judge the convergence of my simulation. But I also heard about that some CFD engineers also care about how much residual drops from the initial condition. I'm wondering is that value useful? Why? What does it imply?
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Best regards, Meimei |
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April 8, 2014, 05:33 |
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#2 |
Member
venki
Join Date: May 2011
Posts: 84
Rep Power: 14 |
some times residual will be converged but solution wont converge, in that case you have to monitor some parameters in critical region, we have to check wheather it is stablized
Usually we will look convegent trends from intial stage |
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April 8, 2014, 05:36 |
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#3 | |
Senior Member
Meimei Wang
Join Date: Jul 2012
Posts: 494
Rep Power: 15 |
Quote:
But still that question, why some engineers care about the drop of the residual from the initial condition but not the residual value itself?
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Best regards, Meimei |
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April 8, 2014, 05:55 |
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#4 |
Member
venki
Join Date: May 2011
Posts: 84
Rep Power: 14 |
(Source-ESI)Only upon looking at the drop in residuals can we get an indication of the overall level of convergence. The rule of thumb is to look at the first residual or the maximum residual calculated and then look for 3-5 orders of magnitude drop from there.
http://support.esi-cfd.com/esi-users/convergence/ You can more idea from this link |
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April 8, 2014, 06:28 |
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#5 | |
Senior Member
Meimei Wang
Join Date: Jul 2012
Posts: 494
Rep Power: 15 |
Quote:
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