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chamber simulation problem

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Old   June 25, 2013, 08:01
Default chamber simulation problem
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hamed
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Hi everybody,

Im simulating the air flow into a chamber. the dynamic mesh was generated by using ESE chamber modeler in AVL Fire v2011. each time I want to start the simulation from the beginning (370 CA), around 435 CA I have a lot of problems with run. in fact turbulent energy and dissipation rate residuals do not behave well and have a oscillating shape. is there anyway to get rid of it?

regards,

hamed
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Old   June 26, 2013, 22:00
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Myunghwan Kim
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Hi hamed,

Frankly, your explanation is too vague.
I guess your problem happens during intake stroke.

In this kind of case, the problem may be very specific to your model.

But in general, I can say you should check the followings.
- check the mesh quality for whole dynamic mesh
==> you can use the cell quality check during dummy run
- boundary condition
==> inlet/outlet condition
- timestep (delta CA and engine speed)
- min. and max. iterations
- relaxation factors
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Old   June 29, 2013, 07:48
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hamed
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Hi,

Thanks for response
I lowered the underrelaxtion factor of turbulent dissipation rate and the simulation resumed.

regards,

Hamed
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