Savonius
/səˈvəʊnɪəs/noun
Attributive Designating a rotor or turbine consisting of two opposed hollow semi-cylindrical blades typically mounted on a vertical shaft, and now used in various forms to measure the speed of air and water currents and in some wind turbines.
Origin
1920s; earliest use found in Mechanical Engineering. From the name of Sigurd Johannes Savonius, Finnish engineer, who developed the turbine.