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initialization - Turbulent KE

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Old   May 12, 2004, 10:51
Default initialization - Turbulent KE
  #1
co2
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hi all,

i have a fluent model where there is a air fluid zone above a porous zone. the problem is natural convection in stored grain. The model is going well and showing good convergence but I have one concern.

When I initialized the problem I initialized k = 6e-6 and epsilon = 1e-9 Those values were calculated from the turbulent intensity assumed at the top pressure outlet of the tank. now the porous zone is laminar zone (check box in porous zone ON) and when I see the results after a few hours of simulation, i see the turb intensity in the porous zone to be around 1e-8 -- Thus it has come down by a order of 100 from the initialization but I was just wondering if the results are correct since in the laminar zone there should not be any turb intensity -- right ? or it is only going to come down slowly as the solution progresses ?

please let me know if you need any more info to answer my question
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Old   May 13, 2004, 07:07
Default Re: initialization - Turbulent KE
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Mattias
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Hello co2!

When turning on the laminaar check box in the porous zone there is no turbulent production in the zone. However, when you initialize, you set an intensity and I guess that you donดt have set relaxation factor for k and epsilon to 1 (default is 0.8 I think). Try patching k and epsilon values to 0 in the porous zone. Then there should be no turbulent intensity in the porous zone.

/Mattias
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Old   May 13, 2004, 12:06
Default Re: initialization - Turbulent KE
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co2
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Mattias :

Thanks for your reply!

I just patched it in the middle of the solution, I am still getting good convergence. so I guess I am ok.

Thanks, Co2
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