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Old   January 3, 2011, 02:13
Default fluent define limiting time
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ekkapong
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Dear all
please give me your suggestion about how to set fluent simulation for limiting time. for example



I have model as shown upper figure.

fluid inlet: 1.8 m/s, 588 k
fin that is surrounded by fluid: 273 k teperature
outlet: outflow

the fluid will transfer the heat to the fin.

I'd like to use CFD postprocessing(temperature contour) after 20 second.
please help me
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Old   January 3, 2011, 03:10
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Can I set time to Transient on General settings and set the Run calculation as following:

Time step size(s)=1
number of time steps= 20
max Iterations/TIme step= 10

Could anyone give me your suggestion that it is correct or not? please
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Old   January 3, 2011, 22:07
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Nuengao,

Your approach is correct. The final time of the simulation will be:

N*\Delta t

Where N is the number of time steps and \Delta t is the time step size.

Typically, having a transient simulation converge (per time step) in 5-7 iterations is reasonably good, thus having a setting of a maximum of 10 iterations per time step is OK. However, in your case I would be concerned about the size of the time step -- ensure that the simulation is actually converging after 10 iterations, not simply marching to the next time step because of the maximum iteration count you've imposed.

Regards,
ComputerGuy
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