The application relates to unidirectional hydrokinetic turbines having an improved flow acceleration system that uses asymmetrical hydrofoil shapes on some or all of the key components of the turbine. These components that may be hydrofoil shaped include, e.g., the rotor blades (34), the center hub (36), the rotor blade shroud (38), the accelerator shroud (20), annular diffuser(s) (40), the wildlife and debris excluder (10, 18) and the tail rudder (60). The fabrication method designs various components to cooperate in optimizing the extraction of energy, while other components reduce or eliminate turbulence that could negatively affect other component(s).

A fluidic structure configured to be mounted onto the hub of a fluidic turbine comprising a hub that rotates about a center axis, aligned to a main shaft that contributes torque to the main shaft of the turbine via the principle of lift and/or drag. The fluidic structure is mounted onto the hub of a primary turbine that contributes torque to the main shaft through increasing at least one of lift and drag, and the fluidic structure includes two or more curved fluidic elements that extend from an upstream tip that aligns to the center axis of rotation, to a downstream end at a radial position away from the center axis, and rotates about the center axis to contribute torque to the primary turbine; and a sensor positioned at or proximate to an upstream tip of the fluidic structure for determining environmental and turbine conditions and transmits information to a supervisory control and data acquisition system of the primary turbine.

A tapered roller bearing (31a) has a plurality of retainer segments (11a, 11d) each having a pocket to house a tapered roller (34a), and arranged so as to be continuously lined with each other in a circumferential direction between an outer ring (32a) and an inner ring (33a). The retainer segment (11a, 11d) is formed of a resin containing a filler material to lower a thermal linear expansion coefficient. In addition, a clearance (39a) is provided between the first retainer segment (11a) and the last retainer segment (11d) after the plurality of retainer segments (11a, 11d) have been arranged in the circumferential direction without providing any clearance. Here a circumferential range (R) of the clearance (39a) is larger than 0.075% of a circumference of a circle passing through a center of the retainer segment (11a, 11d) and smaller than 0.12% thereof at room temperature.

An airfoil for a wind turbine apparatus includes an airfoil body having an arcuate shape extending between a first end and a second end and an airfoil support secured to a midpoint on the airfoil body and connected to the outer end of the support arm. The airfoil body includes a first portion adjacent to the first end and a second portion adjacent to the second end. The first end and the second end are secured to the support arm, and the body of the airfoil is comprised of material capable of flexing in response to wind pressure. The first and second portions of the airfoil body extend away from each other in an extended position and collapse together in a collapsed position, and the orientation of the airfoil relative to the direction of the wind causes the airfoil to move between the open and closed positions.

A method for controlling a wind turbine includes receiving signals representative of oncoming wind speeds approaching at least a portion of a wind turbine, receiving background noise and signals representative of signal-to-noise ratios corresponding to the signals representative of the oncoming wind speeds, determining an availability-and-atmospheric noise in the signals based on one or more of the signal-to-noise ratios, blade positions of blades of the wind turbine, and the yaw position of a nacelle of the wind turbine, determining a wind incoherence noise in the signals due to a change in the oncoming wind speeds while approaching at least the portion of the wind turbine, determining a net measurement noise in the signals based on the background noise, the availability-and-atmospheric noise, and the wind incoherence noise, and controlling the wind turbine based at least on the signals representative of the oncoming wind speeds and the net measurement noise.

An oscillating water column (OWC) includes a top body and a bottom body. The top body includes a hollow shape, an open top end, an open bottom end, a chamber traversing between the open top and bottom ends, a power take-off system proximate to the open top end, and an air channel proximate to the open top end and the power take-off system. The bottom body includes a bottom heave plate and a plurality of flexible tethers coupling the top body and the bottom body.

A tapered roller bearing (31a) has a plurality of retainer segments (11a, 11d) each having a pocket to house a tapered roller (34a), and arranged so as to be continuously lined with each other in a circumferential direction between an outer ring (32a) and an inner ring (33a). The retainer segment (11a, 11d) is formed of a resin containing a filler material to lower a thermal linear expansion coefficient. In addition, a clearance (39a) is provided between the first retainer segment (11a) and the last retainer segment (11d) after the plurality of retainer segments (11a, 11d) have been arranged in the circumferential direction without providing any clearance. Here a circumferential range (R) of the clearance (39a) is larger than 0.075% of a circumference of a circle passing through a center of the retainer segment (11a, 11d) and smaller than 0.12% thereof at room temperature.

A rotor apparatus for extracting energy from bidirectional fluid flows comprises a first rotor (7) mounted for rotation about an axis of rotation (4) in a first direction of rotation, the first rotor (7) having at least one helical blade (2) with a pitch that decreases in a direction along the axis of rotation (4); and a second rotor (8) mounted for rotation about the same axis of rotation (4) in an opposite direction of rotation and having at least one helical blade (2) with a pitch that increases in the same direction along the axis of rotation (4), wherein fluid exiting the first rotor (7) is passed to the second rotor (8).

A fluid flow nozzle including an elongated first wall and an opposing spaced elongated second wall defining an elongated nozzle volume therebetween, wherein the elongated first wall has a first proximal edge and a first distal edge and wherein the elongated second wall has a second proximal edge and a second distal edge. The nozzle inlet is defined by the first and second proximal edges and an opposing nozzle outlet is defined by first and second distal edges. The elongated nozzle has a cross-sectional shape configured to accelerate a fluid flowing from the nozzle inlet to the nozzle outlet without materially increasing fluid turbulence within the flow.

A conical fan assembly, having a generally conical support member having an exterior surface and a vertical major axis, and a plurality of generally crescent-shaped fan blades extending from the exterior surface of the support member, wherein the plurality of fan blades define a helix configured to urge a fluid to flow in a spiral flow pattern up and around the support member.