A fluid turbine comprises a turbine shroud, an ejector shroud, and a means for extracting energy from a fluid stream. The means for extracting energy is located in the annulus between the turbine shroud and the ejector shroud. High-energy fluid can flow through the turbine shroud to bypass the means for extracting energy. Energy is extracted from the fluid passing through the means to form a low-energy fluid stream. The high-energy fluid and the low-energy fluid can then be mixed. The turbine shroud and/or the ejector shroud has mixing lobes to increase the mixing of the two fluid streams.