Fluent - Time Stepping Method CFL Based problem

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  • Last Post 18 October 2019
rafa08 posted this 09 October 2019

I am having issues to set the time stepping of my simulation, i am trying to use a variable time stepping method and i have choose CFL based. my problem is the time step change just when the simulation start, but once it gets the minimum time step size it keep fixed in that even though the max convective courant number is way lower than 0.8.

Thanks for anyone's help!

 

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abenhadj posted this 10 October 2019

You are using at least 2 fixed time step sizes. Please check in Fluent transcript if the behaviour is as your settings. You can report plot time step size too.

Best regards,

Amine

rafa08 posted this 15 October 2019

I have checked and the behaviour is as I am setting. My problem is the time step is always going down and it never increase eventhough the courant number is lower than 0.8. am i doing something wrong? in which cases i can used CFL based time stepping method?

I would expect time step to decrease, but once it stabilizes would hope it increase. why is fluent not updating the time step if the courant number is lower that 0.8?

abenhadj posted this 16 October 2019

Please insert the plot of the time step size?

Best regards,

Amine

rafa08 posted this 18 October 2019

I changed the time step to 2e-5, after that it went down to 1e-5 which is the minimum time step size step size

Thanks! 

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