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Old   July 14, 2011, 16:21
Default Implicit Timestep
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Hi, I had a quick question dealing with time steps in an implicit solution. I am dealing with transient system and finding that 1e-7 was taking to long to stabilize, so during the middle of the simulation i stopped and changed the time step to 1e-6. My question is will this introduce error, I do fully understand higher time step yields solution faster with less accuracy, my question deals more with am I creating a hole or effecting the results in a way that would invalidate them.

So I guess I am asking, does changing the time step create unacceptable noise in the solution after the change. I am actually only interested in the steady state solution, so I am not sure if it even matters.
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Old   July 21, 2011, 00:59
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It is a common practice, for unsteady flows, to start with a low TS and then gradually increase it as time progresses. It will not affect your flow as long as the higher TS leads to a converged flow. Check the value of Courant Number in your domain whenever you adjust the TS, a value <10 should be acceptable.
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