Hi,
for our project we are currently trying to replicate the perfomance of a venturi pump (that we bought) in a simulation: https://www.amazon.com/V-Pump-060400-Multipurpose-Submersible-Pump/dp/B00C2PT9BM This pump is optimized to have a good mix-in (for each 1 part of fresh water it's pulling 4 parts of water in from its surround) and we confirmed that in our experiments. We have replicated the geometry of this pump in Comsol, exploiting the rotation symmetry of its main features (attachment geometry.png).
Water is flowing in from the top and from the cylindrical side walls and is flowing out at the bottom. We've set the inflow rate from the top to 19 L/min and the pressure at the bottom is set to neutral. We would consider the simulation a good match to reality if we had an inflow from the side of 76 L/min at a slight underpressure of about 200mbar. In reality, with 200mbar underpressure we are only seeing 9 L/min (see results.png). Any advice would be highly appreciated!