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Old   October 29, 2013, 12:43
Question The end of unsteady flow
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Hi.
I am modeling an unsteady flow in fluent(implicit). With changing the time step, i can achieve to converging, but after converging the iteration is continue, so How can i understand the simulation is done and i can export the results?
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Old   October 30, 2013, 01:42
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by decreasing (I suppose) the time step size (dt), your solution converges faster FOR A TIME STEP (t). That means the solver switches on next time step (t+dt) untill time step t reaches the number of time steps you set (N)
In this example, dt = 5e-5 s
N = 2000
That means calculation will be over for t = N * dt = 2000 * 5e-5 = 0.1 s
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Old   October 30, 2013, 06:12
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Thank you for reply
1- In my case, by decreasing the time step size (dt), the residuals are going up and more diverge .
2- I do not anything about the time of ending the flowing in my model, so which time i should stop the processing?
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Old   October 30, 2013, 06:26
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1- weird
2- it depends on what you want to compute (your physics)
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Old   October 30, 2013, 06:41
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Can i stop processing when the results do not change after more iterations?
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Old   October 30, 2013, 07:12
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For sure
(you should ask: "Can i stop processing when the results do not change after more time steps")
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Old   October 30, 2013, 08:35
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I am asking: Can i stop processing when the results do not change after more time steps ?
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Old   October 30, 2013, 08:44
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Quote:
Originally Posted by -mAx- View Post
For sure
I already answered, so yes you can
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