Learning Forum

[DaAu]

I am conducting a multiphase flow simulation using the VOF approach and employing the implicit VOF method. What would be an appropriate value for the global Courant number when using adaptive time stepping?

For explicit methods, it is common to select a value around 1 based on the CFL condition. However, how can the Courant number be estimated for the implicit method?

Thank you very much for your answers!

[Rob]

There's an element of guesswork needed. As a starting point work out the time step so flow crosses a cell in one step; divide that by 10 to get the initial time step. If it converges, good, otherwise decrease the step by a bit.