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May 30, 2016, 00:04 |
physical time scale && advection time
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#1 |
Member
SMN
Join Date: Jun 2009
Location: CANADA
Posts: 71
Rep Power: 16 |
Hi,
I am simulating steady state flow over a hydrofoil, but it doesn't converge to error less than 1e-4. I have read alot about the effects of time scale on the convergence, but still do'nt know how I can choose an appropriate physical time scale based on the advection time (reported at the end of out file). I mean is there any relationship between these parameters? thanks, |
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May 30, 2016, 00:32 |
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#2 |
Member
ali
Join Date: Feb 2011
Posts: 37
Rep Power: 15 |
If you have no idea about the physical time scale for your problem, I think it's better to choose automatic time instead. it should be noted that sometimes bad mesh quality leads to high residuals and you cannot reduce them even by setting a very small timescale.
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May 30, 2016, 01:38 |
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#3 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,665
Rep Power: 143 |
This FAQ covers it: http://www.cfd-online.com/Wiki/Ansys...gence_criteria
In your case as you have a free surface it is highly likely that a steady state result is not possible (or at least not easy) and you will have to run transient to get it to converge. |
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