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Changes in large and small time-step

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Old   May 7, 2013, 16:06
Default Changes in large and small time-step
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Natali
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Hello Everyone,
I have a fundamental question.
Is that true that we should expect a change inside the flow happens earlier with a larger time-step size?
I am simulating a transient problem. However, I am using 2 different time-step sizes, 0.00001 s and 0.01 s. But, the changes in the the flow characteristics are exactly the same.
Why that happens?
Thanks,
Natali
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Old   May 7, 2013, 16:45
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Stephan Langenberg
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I don't know if it's a generell procedure, but sometimes smaller time steps are helpfull to start the simulation. In some cases it is necessary two get down with ones time steps in order to start the simulation and don't get trouble with the residuals.
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Old   May 7, 2013, 16:50
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Natali
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Quote:
Originally Posted by Jim87 View Post
I don't know if it's a generell procedure, but sometimes smaller time steps are helpfull to start the simulation. In some cases it is necessary two get down with ones time steps in order to start the simulation and don't get trouble with the residuals.
Thanks,
You know, I start simulation with a small time-step.
Then I have to change something.
I tested this change by a large and small time-step size.
However, the changes are exactly the same. that is completely odd.
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