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unstability in semi-implicit method

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Old   May 8, 2003, 13:01
Default unstability in semi-implicit method
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oishi
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I'm working on numerical solutions of free surface problems for imcompressible Newtonian fluids in two dimensions using finite diferences.

I'm implementing a semi-implicit method for working with problems with a low Reynold's number (Re<1), but I'm having problems of numerical unstability for some values of the time step. I'd like to know how I should work with the time step for avoiding such unstability or references about this problem.

Obs. I'm following the stabilty condition CFL.

Thanks in advance Cassio Oishi
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Old   May 10, 2003, 21:36
Default Re: unstability in semi-implicit method
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Linfeng BI
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Other terms such as the diffusion term also have restrictions to the time step. CFL number only serves as a time step restriction to the convection term.

Employing a better time integeration method can help get a bigger time step.

Linfeng.
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