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non-linear terms in conservative or non-conservative form |
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May 24, 2012, 06:56 |
non-linear terms in conservative or non-conservative form
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#1 |
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May 24, 2012, 11:28 |
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#2 |
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Filippo Maria Denaro
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yes, the discrete equations can drive to very different results (e.g. different wave propagation), as advice you must use always the conservative form!
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May 24, 2012, 11:39 |
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#3 |
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Thanks very much.
On a slightly different note, if the non-lineaity was in an unsteady term for instance , how would one go about discretizing with respect to time? Say, Explicit Euler was being used, would it be possible to just find at the next time step and take the square root of that or is there more to it due to the non-linearity? I think this would reduce the accuracy but I am not really sure. Thanks again! |
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May 24, 2012, 11:46 |
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#4 |
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Filippo Maria Denaro
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Quote:
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May 24, 2012, 13:51 |
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#5 |
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cfdnewbie
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Just as a quick addition to this: There's something called the "skew symmetric form" that avoids aliasing errors and consists of a combination of both formulations. In that sense, it might not always be advisable to use the conservative form alone, but on general, yes, use it rather than the non-con form!
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May 31, 2012, 12:37 |
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#6 |
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Thanks!
Can I just ask more specifically why the conservative form is preferred. If you know any good reading material on this specific topic , please let me know. |
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May 31, 2012, 12:59 |
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#7 | |
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Filippo Maria Denaro
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then, many papers in journals are more specific in analyzing the properties of the conservative (divetgence) form in terms of accuracy and stability |
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June 1, 2012, 00:20 |
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#8 |
Super Moderator
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If solutions are discontinuous, then conservative form should be used.
For smooth solutions, the skew symmetric form can be used; it conserves energy and thats one of the reasons it is used. |
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