A Savonius rotor used as a speed measuring device was subjected to a unidirectional unsteady flow having a mean value U0. A comparison between the rotor rotation rate in this unsteady flow and its rotation rate in a steady flow U0 yielded systematic errors in velocities as inferred from steady-state calibrations. Further dependence of the errors on dimensional quantities suggests that pr esent attempts to model the Savonius rotor's dynamics will have to be expanded.
Karweit, Michael. 1974. "Response of a savonius rotor to unsteady flow." Journal of Marine Research 32, (3). https://elischolar.library.yale.edu/journal_of_marine_research/1295