Implementation of the Courant Number and time stepping in BubbleFoam
 

Dear all,

I´m new to OpenFoam and currently working on understanding the procedure of BubbleFoam.

Therefore, I tried to make the calculation of CoNum and Max Ur Courant number as well as SetDeltaT plausible. In CoNum I don´t understand WHY phi is used to get the velocity: u=phi/area. Same in Max Ur Courant number: WHY using |phir|/|Sf| to get |Ur|? And what does the reciprocal of center to center distance projected over the face normal (with a stabilization factor) of cells' shared face "nonOrthDeltaCoeffs" calculate mathematically (why factor 0.05, unit area)? Regarding the time stepping: Where does the factor "deltaTfact" come from? Why does it have such a form (min(min(...)))? Why factor 1.2? Why maxCo/CoNum?

Can anybody please help me understand this?

Thanks.