Abstract: A diffuser for a wind turbine where slots in said diffuser wall entrain air to enter into the diffuser with a swirl that is counter to the internal swirl created as a reaction to the turbine blades rotation as it extracts power such that the internal swirl and the externally introduced swirl cross over each other thereby causing vortices to form between them that energizes the internal flow and helps to prevent it from separating from the internal duct wall.

Abstract: A submerged flow augmented shrouded turbine power generation system with a forward flow compression section (11) and an aft multi-finned diffuser section (14) with a centrally supported generator (12) powered by turbine blades (15) optimized to be driven by the enhanced flow field created by the forward cowl and aft diffuser/fin sections. The system can be positively buoyant and tethered to the seafloor (18) or negatively buoyant and tethered to the underside of a vessel or offshore structure, or it can be attached directly to the underside of a vessel or offshore structure. An array of such systems can be placed on the seafloor to create a distributed power generation network. An array of such systems can also be placed on the seafloor to directly pump seawater to an energy storage device or a central desalination plant.