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Oscillation of adaptive time step--please help

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Old   February 7, 2003, 16:26
Default Oscillation of adaptive time step--please help
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Sisiya
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Hi, there: I met with some special problem when using adaptive time step. what I did is rather simple, using smaller dt when quantity F changed fast with time, and using larger dt when F changed slower with time. But everytime when I switched the dt, I have some oscilation in F, which is not there if using uniform dt.

BTW, I used the same adaptive method for my 1D codes, it worked. but for 2D, such problem comes. does anyone know how to solve the problem? I appreciate your advice and suggestions very much!
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Old   February 9, 2003, 03:17
Default Re: Oscillation of adaptive time step--please help
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versi
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You are required to switch Dt smoothly in between, just as for grid.
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Old   February 11, 2003, 16:19
Default Re: Oscillation of adaptive time step--please help
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Sisiya
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I have tried to change it smoothly, but seems to me no much help. BTW, I use semi-implicit scheme, so that I need not to abide by the CFL limit. Is it true?
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