Reply To: Examples of free surface: Changes in density and velocity in gas cell
Dear Takayuki,
Your intuition is correct – gas cells do undergo collision and streaming. They are however not coupled to interface or fluid cells. They are essentially “passive observers”, only used to compute the zero-pressure boundary condition on the interface, without any mass or momentum transfer.
If you would like to learn more, feel free to ask here or refer to our code in:
All the best,
Tikhon Riazantsev