How to get this rotation to work?

Hello, i’m doing a game design project with a group and at the moment I am doing a puzzle where a watermill rotates around when You push it with wind, I have set it up with a cylinder while I await the 3d models from the modellers however I can’t seem to get it to rotate in the correct direction, I just want it to go round in the following direction similar to that of a waterfall, can anyone help with this?