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Old   March 26, 2009, 15:34
Question DPM post proc problem
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Stel_K is on a distinguished road
hello

i am trying to simulate a simple case of turbulent flow with a backwads step to see and understand how DPM is working. later i will upscale to my own work.

the flow simulation is steady and so is the particle tracking in the DPM options. i am using the stochastic option with the discrete random walk model. i have solved and iterated for the flow field first and then i have specified DPM and tried to display particle tracks with no further iterations.

problem is that every time i click display i get a different display view, ie. particle path or paths. so my question is whether or not this is normal? is it because fluent uses a different initial value every time it solves the DPM? if this is what should be happening how do you get a mean path? or a value that is useful? or you just choose the one you like from all those suggested?

if the above is not right what am i doing wrong?

any replies and thoughts would be much appereciated.

thank you
stelios
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Old   March 27, 2009, 10:42
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Hi,

what are you saying is right. You are using a stochastic representation so you can't expect to see exactly the same paths. But pay attention to the fact that if you are using the random walk model you should have a realistic representation from a statistical point of view. Therefore the value for "number of tries" should be enough high to obtain statistically indipendent results.

Hope this help,

Cinzia
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