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Rayleigh number Custom field function

Hi ,

I would like to plot a custom field function of Rayleigh number with time in Fluent. ( I am simulating a natural convection problem in a 3D rectangular enclosure ). The formula for Rayleigh number is $Ra = \frac{g \beta \Delta T L^{3}}{\nu \alpha}$ . I would like to get the values of these fluid properties from the simulation.

The problem is i am unable to find these properties and constants $g, \beta ,\Delta T , L , \nu , \alpha$ inside custom field function in fluent while defining the cff. Is there a solution to this problem ? Can anyone guide me on how to implement it ?

Thanks in advance.

It will be certainly helpful if some can help me on this issue. It might seem trivial to some of you but can help a lot in getting ahead in the learning curve.

Quote:

Originally Posted by praphul (Post 667705)

You know g is 9.81; Your beta is thermal expansion coefficient, which is 1/T (1/fluid temperature). L is characteristic length which is Volume of the body/Surface area of the body; Dynamic viscosity (Nu) , Diffusivity (alpha) can be easily found onlne at the corresponding fluid temperature