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SERVIGNAF December 20, 2010 16:36

RMS Courant Number
 
hi...how to calculate the RMS courant number.....is (velocity*deltaT)/element size?? in my project I have a courant number values equal to 999.99, where this affects the solution to my problem? and how I can do to lower that value?

Thanks...

ghorrocks December 20, 2010 18:04

The documentation describes the calculation of Courant number.

Don't get too excited about the Courant Number. Do a time step sensitivity check instead to give you the time step your model can run at.

To lower Courant number you run a smaller time step.

SERVIGNAF December 21, 2010 08:30

THANKS. But I still doubt, do not know if it is conceptual, I need to see the cooling behavior of a solid body by convection, for about 10 hours, then if I use this time as total transient simulation, it appears a number of high courant. Will need to divide this time segment? or just change the steps of time?

Josh December 21, 2010 17:07

I like the adaptive time scheme. Set a reasonable residual value (you'll have to determine what this is) and the program will lower or raise the timestep size based on the convergence speed. It will give you an approximately appropriate timestep size.


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