I have modest experience in using COMSOL, very limited in fluid flow modelling.
I've encountered a new type of problem for me, & so far cannot 'get started'; any pointer to similar examples etc would be most welcome.
Imagine a conical vessel, small end down, with a short outlet tube at the bottom to a free exit - a funnel. Liquid flows out under gravity. Liquid is poured in, and can be adequately simulated by a small central area with a defined flow on the upper surface. As the inlet flow increases, the level in the vessel rises, the outlet flow rate increases, & a new equilibrium is reached. So the upper free surface moves up & down in response to inlet flow changes, & the vertical position of the inlet port also changes. How does one cope with that? Can anyone point me to a related example please?
The flows are slow, we expect a re-circulating flow pattern, with axial symmetry. Later we will need to add thermal transport.