Rotor for operation in a flow medium

A rotor for a wind power plant for operation without the influence of flow-guiding stationary housings or channels in a flow medium contained in a space of unlimited dimensions as compared to the rotor dimensions, comprising one set of rotor blades and a shroud arranged in the region of the periphery of the rotor having an axis and formed as an axially symmetrical outer annular shroud rotating in unison with the rotor, said outer annular shroud in a cross-section lying in an imaginary plane extending through the rotor axis having a profile the angle of attack of which is greater than its critical angle of attack with respect to a flow direction extending parallel to the rotor axis, said profile being adapted to generate a lift force under the effective flow conditions given at rotation of the rotor within the operational rotational speed range, and being oriented such that its suction side forms the inner side of the annular shroud, said profile having a downstream portion extending outwardly at a large angle away from the rotor axis and substantially transversely thereof.