Abstract
The Sedláček's turbine (known as SETUR) is an interesting hydraulic device that converts hydraulic energy into mechanical motion. The rotor in this turbine is blade-less and has a completely smooth shape.
To find a physical explanation of its operation is an open problem, which we tackle here. Our theory is based on the idea that the fluid force on the rotor exists as a positive feedback to the orbital motion of the rotor.
This is explained in a theoretical computation and supported by a numerical experiment.