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Issue with Flow Time Step choise

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Old   June 25, 2014, 07:05
Question Issue with Flow Time Step choise
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Hi all,

I'm simulating with DEM dropping of particles to mesure the variation of the Reposal Angle due to other parameters.

But I have a problem in choosing the correct Flow Time Step.

I'm simulating ONLY the discrate phase, whose equation are integrated using a Particle Time Step, that is much smaller than the Flow one, so the Flow Time Step last shouldn't affect the results, couse it is not used.

Unfortunately it does.

So, some of you knows if the Flow Time Step is definetely not affecting the results, and i can choose it freely? (it wuold mean that i have some other mistkes somewhere)

And in general, do you know if changing the Flow Time Step, in the middle of a simulation, and continue the simulation with a different FTS can affect the results?

I attached the picture of an heap of particles obtained by tracking particles with Particle Time Step and a "flat one" obtained by tracking particles with Flow Time Step
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File Type: jpg normal_heap.jpg (74.3 KB, 9 views)
File Type: jpg flatheap.jpg (78.5 KB, 7 views)
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