# HELP TIME STEP!!

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 March 21, 2004, 16:30 HELP TIME STEP!! #1 merry Guest   Posts: n/a Sponsored Links Hello I am computing an unsteady flow around an obstacle in fluent 6.1. First, I made computations with the steady case. And then when the solution converged I turn on the unsteady case. I calculated the time step ( time step = T/100= 1.e-3 s) from the strouhal number that gives the shedding frequency (f= 1/T)of the vortex. The problem, when I started the computations with this time step the solution converged after the 1st iteration. So, I increased the time step (1.e-2) but still the solution is converging after the 1st iteration. and then I increased the time step again and again and again.... every time the solution is converging after the 1st iteration. So, I really don't know what fluent is doing ???? it seems that for any time step the solution is converging. Can someone explain what is really happening??? thanks Merry

 March 25, 2004, 14:35 Re: HELP TIME STEP!! #2 Zhihua Guest   Posts: n/a I think you can change the convergence criteria in Fluent. It is located at Solve-Monitor. Set a much lower value for convergence of any equations.

 March 25, 2004, 15:38 Re: HELP TIME STEP!! #3 merry Guest   Posts: n/a thanks a lot for your suggestion. I'll try that!

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