A drag-based wind turbine device is disclosed. The device is an improved wind turbine comprised of two sets of stacked and coupled, drag-based vertical axis wind turbines, wherein drag from the first turbine helps propel the second turbine. Additionally, the surface of the first turbine is convex to ensure wind is always deflected toward the second turbine, wherein the wind is then received by the concave side of the second turbine. Further, the blades are arranged in a horizontal and sloping manner. In the convex position, each slope blade deflects incoming wind to the other set of turbines in a concave direction. Additionally, the gap between two turbines can be adjusted for different wind/current speeds, viscosities, compressibility, and densities for the best efficiency.

A windmill rotation restrictor device restricts the speed of rotation of front blades of a decorative windmill in high winds. The device includes a windmill having a base, a rotor, and a vane. The rotor includes a front blade assembly and a front shaft extending from the front blade assembly. The front shaft is freely rotatable relative to the base. The vane includes a rear blade assembly and a rear shaft extending from the rear blade assembly. The rear shaft is freely rotatable relative to the base. The front blade assembly and the rear blade assembly rotate in opposite directions when blown by wind from a single direction. A linkage couples the front shaft to the rear shaft such that rotation of the rear blade assembly counteracts and slows rotation of the front blade assembly.

A method of controlling a floating-body wind turbine power generating apparatus including a wind turbine generator disposed on a floating body includes a pitch-angle increasing step of increasing a pitch angle of a blade of the wind turbine generator when the wind turbine generator is stopped, so that an aerodynamic braking force is applied to a rotor of the wind turbine generator. In the pitch-angle increasing step, a first change rate of the pitch angle of the blade in a first period during which the wind turbine generator is in an inclining motion toward an upwind side from a vertical direction due to sway of the floating body, is smaller than a second change rate of the pitch angle of the blade in a second period during which the wind turbine generator is in an inclining motion toward a downwind side from the vertical direction due to the sway of the floating body.

A method of controlling a floating-body wind turbine power generating apparatus including a wind turbine generator disposed on a floating body includes a pitch-angle increasing step of increasing a pitch angle of a blade of the wind turbine generator when the wind turbine generator is stopped, so that an aerodynamic braking force is applied to a rotor of the wind turbine generator. In the pitch-angle increasing step, a first change rate of the pitch angle of the blade in a first period during which the wind turbine generator is in an inclining motion toward an upwind side from a vertical direction due to sway of the floating body, is smaller than a second change rate of the pitch angle of the blade in a second period during which the wind turbine generator is in an inclining motion toward a downwind side from the vertical direction due to the sway of the floating body.

The invention relates to a device of a safety system and/or resource and energy-efficiency improvement system for influencing the flow around an aero- or hydrodynamic body, preferably an aerofoil, according to the principle of a back-flow flap, characterized in that: said device, together with the aero- or hydrodynamic body, in particular aerofoil, form at least a partial shift of the delimitation of the flap region by means of the back-flow flap and the delimiting component thereof when the back-flow flap is partially and/or completely raised, thus influencing the trailing edge separation vortex/vortices and/or the flap separation vortex/vortices; and in that the delimitation of the flap region shifts completely up to or beyond the profile trailing edge, or shifts only to a section in front of the profile trailing edge. The delimitation component is movably connected to the aerofoil by means of a basic element and is preferably permanently secured and/or releasably secured for maintenance purposes, thus ensuring a long service life for the rotor blade and/or wind turbine and/or flap system, preferably >5 years, particularly preferably >10 years, and most particularly preferably >=20 years, and/or thus optionally allowing simple removal/replacement.

An inexpensive modular micro wind turbine system is designed for residential as well as commercial and other installations in low-wind and high-wind environments. Simple replaceable components are easy to manufacture, install and sell in small flat packages to facilitate retail distribution (as a single standalone wind turbine module or a cascading series of daisy-chained modules). A substantially enclosed architecture and airfoil design prevents air molecules from easily escaping, providing a number of benefits over existing mast and propeller designsincluding enhanced safety, noise reduction, improved energy efficiency and a self-braking effect that causes the rotational speed of the wind turbine to reach an equilibrium before reaching a maximum survival speed, thereby enhancing safety while avoiding the need for an external braking mechanism. An integrated generator (including conducting coils in each stator in proximity to magnets in each rotor) avoids the need for an external generator.

A lift modifying device for a rotor blade of a wind turbine is provided, the lifting modifying device including at least one fluid jet module and at least one compressed fluid source, wherein the at least one fluid jet module includes multiple fluid jets, which are fluidically connected to the at least one compressed fluid source, the at least one fluid jet module is configured to be arranged at a suction side or a pressure side of an airfoil of the rotor blade, and the at least one fluid jet module is configured to generate a fluid curtain separating an air flow on the suction side or the pressure side of the airfoil, when the rotor blade is provided with the lift modifying device on its suction side or pressure side and the at least one compressed fluid source supplies compressed fluid to the at least one fluid jet module.

A rotor blade of a wind turbine is provided, the rotor blade including a lift modifying device having at least one fluid jet module and at least one compressed fluid source, wherein the at least one fluid jet module includes multiple fluid jets, which are fluidically connected to the at least one compressed fluid source, whereby the at least one fluid jet module is mounted as an add-on onto an outer surface of the suction side or the pressure side of the rotor blade. Also provided is a method for installing this rotor blade, whereby a rotor blade is provided and the at least one fluid jet module is mounted as an add-on onto the outer surface of the suction side or the pressure side of the rotor blade.