A shrouded fluid turbine comprises an impeller and a turbine shroud surrounding the impeller. The inlet of the turbine shroud is flared. The shroud includes alternating inward and outward curving lobe segments along a trailing edge of the turbine shroud. The inward and outward curving lobe segments have exposed lateral surfaces, or in other words do not have sidewalls joining the inward and outward curving lobe segments. This allows for both transverse mixing and radial mixing of air flow through the turbine shroud with air flow passing along the exterior of the turbine shroud.