A wind turbine device may include four wings. A first wing may include a first leading edge and a first trailing edge, and a second wing may include a second leading edge a second trailing edge. The first and second leading edges may be positioned on opposite sides of the axis of rotation, the first and second trailing edges may be positioned on opposite sides of the axis of rotation, and the first and second leading edges may be positioned relatively closer to the axis of rotation than the first and second trailing edges. A third wing may include a third leading edge and a third trailing edge, and a fourth wing may include a fourth leading edge and a fourth trailing edge. The third and fourth trailing edges may be each positioned proximate to the axis of rotation and positioned on opposite sides of the axis of rotation.

A vertical-axis wind rotor configured by concave-convex type airfoil profiles in the form of vertical helical protrusions, tilted towards counter-rotation and twisted around, the chord decreasing, where both ends are finished in the form of sharklets rotated towards the upper surface so as to eliminate the vortex, and distributed in a circular pattern around the rotation shaft thereof. The angular arrangement of the chord of the section of the profile with a spoke with respect to the shaft of the rotor is particular for making the profile work under lift conditions before reaching the normal under drag forces and complementing them, eliminating jerking, with the direction of rotation being indicated by the Coriolis effect and determining the radial distribution, the radius, the chord, the profile, and the number of them, which confers to the rotor the maximum terminal velocity at which it slows down, being maintained by the Magnus effect.

Disclosed is a blade shell section of a wind turbine blade, such as wind turbine blade with a flatback section. The blade shell section extends in a longitudinal direction from a first shell section position to a second shell section position. The blade shell section comprises a first laminate layer forming the outer surface of the blade shell section and a second laminate layer forming the inner surface of the blade shell section. The blade shell section further comprising a first shell section and a corner shell section between the contour shell section and the flatback shell section.

A centrifugal compressor impeller includes a plurality of blades on a front side that extend from a first axial side to an outer radial end of the impeller. The centrifugal impeller includes a back side having a nonlinear backwall. The backwall can include a flat area hear a bore of impeller, a flat area near a tip of the impeller, and a convex surface between the flat areas of the bore and the tip. In some forms the impeller further includes a concave surface between the convex surface and the tip to form an s-shape. A transition or inflection point can denote the change from convex to concave. The convex and/or concave surfaces can take any variety of forms such as constant radius sections and/or compound curves.

A hydrokinetic energy conversion system (1) comprising a turbine device (2) comprising a rotor (3) displaying a rotational axis (O), which turbine device is arranged to operate with the rotational axis in an inclined orientation vis--vis an incoming body of water (W), and which rotor comprises a blade (10) which is arranged to interact with the incoming body of water such that rotational energy is imparted to the rotor. The blade comprises a first, convex surface (12), a second, concave surface (13) and a free, distal edge (E) where the first surface and the second surface meet. The curvature of the second surface, when viewed in a plane orthogonal to the rotational axis, is such that a maximum depth (Dmax) of the second surface, when measured from a straight line intersecting the rotational axis and the distal edge, is at least 35% of the distance between the rotational axis and the distal edge.

A fluid flow turbine having a turbine rotor with a plurality of blades (also known as vanes) for converting the kinetic energy of a flowing fluid into mechanical rotational energy of the turbine rotor is provided by this invention. The plurality of blades are defined by a continuously sinuous curve outer edge that results in the lateral surface of the blades having a lower concave portion for scooping up the horizontal incoming fluid flow and redirecting it to a substantially vertical fluid flow along the lateral surface of the blade. The upper portion of the lateral surfaces of the blades is convex, causing the upper edge of the blades to tail off laterally so that the fluid flow exits the turbine in a substantially vertical direction, instead of turning back upon itself to reduces turbulence of the fluid flow inside the turbine. The fluid flow turbine can comprise a small wind turbine that will produce electrical power at low wind speeds, and can be mounted to the top of a building.

A method of reducing the load of a rotor blade of a wind turbine during installation of the wind turbine, whereby the rotor blade includes an aerodynamic device such as a vortex generator or a noise reducer is provided. The method includes the steps of attaching a cover on the rotor blade for covering at least a part of the aerodynamic device before lifting the rotor blade to the top of the tower of the wind turbine, and detaching the cover subsequently. An arrangement including a rotor blade of a wind turbine and such a cover, is also provided.

A vortex generator for a wind turbine blade to be mounted to a wind turbine blade includes: a platform portion to be mounted to a surface of the wind turbine blade; and at least one fin disposed upright on the platform portion. The platform portion has a cross section having a curved convex shape, at least along a blade spanwise direction of the wind turbine blade.

A fluid flow turbine having a turbine rotor with a plurality of blades (also known as vanes) for converting the kinetic energy of a flowing fluid into mechanical rotational energy of the turbine rotor is provided by this invention. The plurality of blades are defined by a continuously sinuous curve outer edge that results in the lateral surface of the blades having a lower concave portion for scooping up the horizontal incoming fluid flow and redirecting it to a substantially vertical fluid flow along the lateral surface of the blade. The upper portion of the lateral surfaces of the blades is convex, causing the upper edge of the blades to tail off laterally so that the fluid flow exits the turbine in a substantially vertical direction, instead of turning back upon itself to reduces turbulence of the fluid flow inside the turbine. The fluid flow turbine can comprise a small wind turbine that will produce electrical power at low wind speeds, and can be mounted to the top of a building.

A vortex generator for a wind turbine blade to be mounted to a wind turbine blade includes: a platform portion to be mounted to a surface of the wind turbine blade; and at least one fin disposed upright on the platform portion. The platform portion has a cross section having a curved convex shape, at least along a blade spanwise direction of the wind turbine blade.