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-   -   Global CFL Setup (https://www.cfd-online.com/Forums/su2/169354-global-cfl-setup.html)

paulzhang April 8, 2016 04:25

Global CFL Setup
 
Hello,

Is there a way to use a global CFL, ramping from a small value up to a user defined upper limit, without modifying the code?

I feel the a universal physical time step for each cell makes more sense than variant one.

Thanks,
Paul

hlk April 11, 2016 12:42

Quote:

Originally Posted by paulzhang (Post 594041)
Hello,

Is there a way to use a global CFL, ramping from a small value up to a user defined upper limit, without modifying the code?

I feel the a universal physical time step for each cell makes more sense than variant one.

Thanks,
Paul

For more information on the current CFL adaptation options see:
http://www.cfd-online.com/Forums/su2...parameter.html

As you can see in the cfd-online entry on the CFL number (http://www.cfd-online.com/Wiki/Coura...Lewy_condition), the CFL number is defined relative to the grid size and so a constant CFL will not necessarily give a constant time step across the mesh. If you would like to use constant time-stepping, you may want to use the unsteady capability. Some examples are in TestCases/unsteady, where you would need to change the UNSTEADY_SIMULATION setting to TIME_STEPPING to get the behavior that I think you are describing.


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