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Meaning of Vmax, dtReq, CFL', CG,... - Printable Version

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Meaning of Vmax, dtReq, CFL', CG,... - catchyid - 07-06-2015

hi,
when hitting simulate, a console screen opens up and display some stats about the simulation, i could not find the meaning of these stats. For example, I "think" CFL' tells the maximum distance fluid has travelled in the grid (so one can lower CFL and introduce substeps if extra accuracy is needed), is this correct. In summary, what's the meaning of :
-Vmax
-dtReq
-CFL
-CG

AND why memory changes twice in each simulation?

Thanks,

Re: Meaning of Vmax, dtReq, CFL', CG,... - sitnisati - 07-08-2015

Hello,

I hope this helps...

-Vmax - the maximum velocity in the grid
-dtReq - dt required
-CFL= CFLCondition*Spacing/Vmax ;
-CG - Conjugate Gradient

Regards,
Kresimir Tkalcec

Re: Meaning of Vmax, dtReq, CFL', CG,... - catchyid - 07-18-2015

Thanks for your reply...

Quote:CFL= CFLCondition*Spacing/Vmax ;

What does that imply in a simulation? i.e. IF CFLCondition = 5 and CFL = 1, would that be a good situation? what's a good value of CFL I need to look for? Finally, what's the unit of CFL (seems like spacing/velocity is time?)

Thanks,

Re: Meaning of Vmax, dtReq, CFL', CG,... - sitnisati - 07-23-2015

Hello,

There is a lot text written about the CFL which can help to understand its meaning in fluid simulations and its explanation is beyond our support.

Regards,
Kresimir Tkalcec

Re: Meaning of Vmax, dtReq, CFL', CG,... - catchyid - 07-28-2015

of course there are lots of text written on fluid dynamics, but the reason anyone is buying your software is to eliminate the need of textbooks reading and focus on visual effects production. if there is a parameter that is hard to explain in plain language then how it's usable to end-user ???? otherwise you should really make it clear that you need to have a prerequisite in fluid dynamics to understand how to use your software....

Re: Meaning of Vmax, dtReq, CFL', CG,... - sitnisati - 07-28-2015

Hello,

We think that that information about the CFL UI parameter inside the help file is quite sufficient for a user to be able to successfully use it. There's actually more explanation than in any other popular fluid dynamics software.

For more detailed information, you will need to get into specific literature.

Thank you.

Regards,
Kresimir Tkalcec