[Andrey.M.]

Hello, dear community of cfd-online!

Since VOF model is of much computational cost, there are 2 important issues:
How fine domain should be meshed and what timestep should be used.
If we have a 2D case of straight channel and to describe cross-section we use say 20 cells in the core and 6 cells per boundary layer to solve homogeneous flow. We want to solve a flow with gas and liquid phases, which volume fraction is 10%. Does it mean that for same accuracy we have to use 10x more cels to describe cross section?
If we have a comparatively large timestep which results in Courant number equal to 30 and each timestep converges, is it still a good solution? What timesteps and Courant numbers could be applied to get a relevant solution with not much time spent on calculation?

Thank you in advance for your answers!