Modelling a partially submerged paddle wheel

Hi all,

I am a COMSOL beginner and am hoping to get some advice on how to use the Rotating Machinery, Turbulent Flow module to model the movement of a paddlewheel through water at a water/air boundary.

I've been working off of the Turbulent Mixing of a Trace Species example from the COMSOL Application Gallery in order to gain a better understanding of the Rotating Machinery, Turbulent Flow module. (LINK: www.comsol.com/model/turbulent...ixing-of-a-trace-species-12727 ) The example involves building a simple 2D mixing vessel composed of a stationary domain that completely surrounds the rotating domain. The rotating domain contains two bezier polygons that represent zero-width impeller blades.

I am now trying to set up a paddlewheel that is half in a water domain and half in an air domain. I tried doing this by creating two adjacent rectangular geometries, defining one as water and the other as air, setting up a rotating domain in between them, and defining an open boundary along the boundaries that the two share. However, this does not work.

If anyone could help me set up this two-domain simulation, I would be very grateful!