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olitchka January 15, 2008 10:31

Courant number star-cd
 
Hi everyone,

I'd like to know if someone did already a 'Courant Number' investigation when using Prostar/es-ice. I am currently trying to fine-tune the time step so as to reduce my multi-cycle calculation time. The user-manual states that the 'local' Courant number has to stay below 100. Does anyone already try to overshoot this value? Is a value around 120-130 still ok?

Cheers!

may be January 15, 2008 18:24

Re: Courant number star-cd
 
no

James January 16, 2008 08:52

Re: Courant number star-cd
 
Often if you run 4 piso stages per temestep you will get the least CPU time per physical time. Therefore if you set your timestep to achieve this you will be doing about as well as you can (all other things being equal).

Obviously the physics of the problem has to allow this and the timestep has to be suitable to capture the necessary temporal details.

Grid generation is also key here as if you put small cells in high velocity zones and they were not needed then it significantly slows the overall progress of the simulation.


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