An apparatus for lifting a wind turbine blade to a rotor hub includes a blade holder configured to receive and support the wind turbine blade. A connection element is configured on the blade holder and is adapted to attach directly to a mounting surface of a wind turbine rotor hub. A lifting equipment attachment is configured on the blade holder to attach to the blade holder to lifting equipment. A first steering mechanism is operably connected between the blade holder and the lifting equipment attachment to control an orientation of the blade held by the blade holder with respect to the lifting equipment attachment.

Airfoil and hydrofoil systems include structures having a surface texture defined by fractal geometries. Raised portions or fractal bumps can be included on the surfaces, forming a surface texture. The surface textures can be defined by two-dimensional fractal shapes, partial two-dimensional fractal shapes, non-contiguous fractal shapes, three-dimensional fractal objects, and partial three-dimensional fractal objects. The surfaces can include indents having fractal geometries. The indents can have varying depths and can be bordered by other indents, or bumps, or smooth portions of the airfoil or hydrofoil structure. The fractal surface textures can reduce vortices inherent from airfoil and hydrofoil structures. The roughness and distribution of the fractal surface textures reduce the vortices, improving laminar flow characteristics and at the same time reducing drag. The systems are passive and do not require applied power.

A rotor blade of a wind turbine is provided, wherein the rotor blade has a flow deflection device for influencing an airflow flowing from the leading edge section of the rotor blade to the trailing edge section of the rotor blade. The flow deflection device passively changes its configuration depending on the bending of the rotor blade. Furthermore, the airflow is influenced such that load on the rotor blade is reduced. Furthermore, a method to reduce load on a rotor blade of a wind turbine is provided.

A spiral blade unit is disclosed, which generates less blade-sagging, deformation, or vibration, can be made of various material, can be made with light material, and can be installed easily in interconnecting spiral blades. The spiral blade unit includes a rotational axle and spiral blades with root portions attached along an outer circumferential surface of the rotational axle, and the spiral blades are interconnected to one another through a blade connector.

A floating wind turbine structure comprising: a rotor carrying at least one blade, at least two support arms supporting a nacelle, said at least two support arms comprising upper and lower portions, said upper portions being associated with the nacelle and said lower portions being associated with means in the shape of floats, at least one support arm located upstream from the rotor relative to the wind direction, at least one support arm located downstream from the rotor relative to the wind direction, characterized in that the rotor is provided with a hollow shaft arranged to rotate about the nacelle.

It comprises a body that has an inertial asymmetrical and/or the body is asymmetrical in terms of geometry and/or mass of with respect to a XZ plane passing substantially through the centre of a wind turbine rotor for withstanding asymmetrical loads acting on the wind turbine. The inertia in sections of the structural member body at one side of the XZ plane may be 50% greater than the inertia in sections of the structural member body at another side of the XZ plane. The structural member may connect the wind turbine tower with the wind turbine rotor and may comprise at least two asymmetrical portions defined on both sides of the XZ plane which may be mutually asymmetrical reinforcing elements.

A method for operating a wind energy installation having a tower, a nacelle arranged on the tower, the azimuth of which can be adjusted, and a rotor having at least one rotor blade, the blade angle of which can be adjusted, in which tower oscillations are detected and monitored during operation using at least one measuring apparatus and power operation is switched off if a sliding average of the tower oscillations exceeds a tower oscillation limit value. The tower oscillation limit value is defined, at least during load operation of the wind energy installation, as at least one limit value function which is dependent on a sliding average of prevailing wind speed and/or a parameter associated therewith, and has different functional dependencies in a plurality of different value ranges of the prevailing wind speed or the parameter associated therewith. The invention also relates to a wind energy installation.

Methods for installing blades of a wind turbine are provided. The method comprises: providing a blade holder, wherein the blade holder comprises a connection element adapted to be attached to a mounting surfaces and a lifting equipment attachment, the blade holder being provided with a steering mechanism. Then, the blade holder is attached to the blade. The blade holder is hoisted with the blade towards the rotor hub with lifting equipment. The blade holder is attached to the mounting surface of the hub using the connection element. The rotor hub is rotated using the weight of the blade holder and the blade to a first desired position for mounting the blade to the rotor hub. The blade holder is detached from the hub. Then, the blade may be mounted to the rotor hub. A wind turbine blade holder for holding a blade and for use in lifting the blade is also provided.

The present disclosure is directed to a vortex generator configured for mounting to either of a suction side or a pressure side of a rotor blade. The vortex generator includes a base portion having a contour in an uninstalled state that substantially aligns with or conforms to a contour of a plurality of locations of either on the suction side or the pressure side of the rotor blade. Further, the vortex generator includes a protrusion member extending upwardly from the base portion. The protrusion member includes a plurality of tines separated by at least one slit. Moreover, the base portion and the protrusion member are constructed of a rigid material. In addition, the vortex generator includes a flexible coating material configured at least partially around the base portion and/or within or around the at least one slit.

Systems for increasing the power productivity of two bladed teetering hinge, yaw controlled wind turbines by varying rotor shaft restraining torque and yaw angle.