Time step

March 14, 2006, 09:40

Hi all how should we decide the time step in an unsteady flow?

March 14, 2006, 12:49

You should set a Time Step Size so that the number of iterations necessary to get convergence at each time step is 5-10. If converce at each time step requires more than 5-10 iterations then reduce the Time Step Size. If converce at each time step requires less than 5-10 iterations then you can increase the Time Step Size.

March 14, 2006, 12:52

You should set a Time Step Size so that the number of iterations necessary to get convergence at each time step is 5-10. If convergence at each time step requires more than 5-10 iterations then reduce the Time Step Size. If convergence at each time step requires less than 5-10 iterations then you can increase the Time Step Size.

March 16, 2006, 08:59

The advise above is acceptable only for small cases when time is not a critical issue.

Your timestep has to be at least 2-5 times less than a period of smallest disturbance in your flow.

March 14, 2006, 09:40	Time step	#1
anand Guest Posts: n/a	Hi all how should we decide the time step in an unsteady flow?

March 14, 2006, 12:49	Re: Time step	#2
dan Guest Posts: n/a	You should set a Time Step Size so that the number of iterations necessary to get convergence at each time step is 5-10. If converce at each time step requires more than 5-10 iterations then reduce the Time Step Size. If converce at each time step requires less than 5-10 iterations then you can increase the Time Step Size.

March 14, 2006, 12:52	Re: Time step	#3
dan Guest Posts: n/a	You should set a Time Step Size so that the number of iterations necessary to get convergence at each time step is 5-10. If convergence at each time step requires more than 5-10 iterations then reduce the Time Step Size. If convergence at each time step requires less than 5-10 iterations then you can increase the Time Step Size.

March 16, 2006, 08:59	Re: Time step	#4
Oleksiy Dushyn Guest Posts: n/a	The advise above is acceptable only for small cases when time is not a critical issue. Your timestep has to be at least 2-5 times less than a period of smallest disturbance in your flow.

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