The present invention relates to a wind turbine blade (10) with an access window (94) extending through a shell body of the blade. A frame (96), which defines an opening (97), is arranged on top of the outer surface of the blade such that the opening of the frame (96) is aligned with the access window. A cover member (92) covers the opening (97) of the frame and releasably closes the access window.

A rotor blade, with a suction side and a pressure side, for a wind turbine, having a rotor blade root of a hub region for attaching the rotor blade to a rotor hub, a rotor blade tip, which is arranged on a side, facing away from the rotor blade root, of a tip region, at least one vortex generator, which is arranged between the rotor blade root and the rotor blade tip, wherein the at least one vortex generator comprises swirl elements with a length and a height, which are arranged one next to the other in a longitudinal direction of the rotor blade and are in each case oriented at an angle to a main flow direction of the rotor blade, wherein, in the longitudinal direction of the rotor blade, the swirl elements have a lateral spacing to one another. A variation in the geometry of the swirl elements is realized in a manner dependent on a respective distance between the arrangement of the swirl elements and the rotor blade root.

Disclosed are methods and apparatuses for mitigating the formation of concentrated wake vortex structures generated from lifting or thrust-generating bodies and maneuvering control surfaces wherein the use of contour surface geometries promotes vortex-mixing of high and low flow fluids. The methods and apparatuses can be combined with various drag reduction techniques, such as the use of riblets of various types and/or compliant surfaces (passive and active). Such combinations form unique structures for various fluid dynamic control applications to suppress transiently growing forms of boundary layer disturbances in a manner that significantly improves performance and has improved control dynamics.

A wind turbine rotor blade is provided, having a root end, a tip end, a leading edge section, a trailing edge section and a serrated extension, wherein the serrated extension is attached to the trailing edge section and has at least a first tooth. Furthermore, the wind turbine rotor blade has at least one patterning element for guiding a wind flow which is flowing from the leading edge section to the trailing edge section such that noise which is generated at the trailing edge section is reduced. The patterning element has the shape of a ridge. Advantageously, the ridge-shaped patterning element is located upstream, compared to the first tooth, and/or is located on a surface of the first tooth. Furthermore, a method is provided to reduce noise which is generated at a trailing edge section of a wind turbine rotor blade.

A fluid turbine has semi-spherical, hollow blades arrayed about a vertical axis. The turbine's blade shape reduces drag on a convex side and increases drag on a concave side. Part of the center of the array of rotor blades is open, allowing flow through the center of the array. The spherical form enhances fluid flow through the center of the array and results in rotational force on a downwind blade, and directs fresh air into bypass flow. A combination of holes and a deflector surface generates vortices as updraft flow passes through holes, creating a pressure differential between the area surrounding the holes and the upper portions of the blade. Fluid passing from relatively higher pressure to relatively lower pressure passes the deflector surface, forming vortices that result in rotational force on the blades of the fluid turbine.

Disclosed are methods and apparatuses for mitigating the formation of concentrated wake vortex structures generated from lifting or thrust-generating bodies and maneuvering control surfaces wherein the use of contour surface geometries promotes vortex-mixing of high and low flow fluids. The methods and apparatuses can be combined with various drag reduction techniques, such as the use of riblets of various types and/or compliant surfaces (passive and active). Such combinations form unique structures for various fluid dynamic control applications to suppress transiently growing forms of boundary layer disturbances in a manner that significantly improves performance and has improved control dynamics.

A wind turbine blade assembly includes a rotor blade having exterior surfaces defining a pressure side, a suction side, a leading edge and a trailing edge, each extending between a blade tip and a root. The rotor blade additionally defining a span and a chord. The blade assembly further includes a plurality of micro boundary layer energizers positioned on a surface of the pressure side of the rotor blade. The plurality of micro boundary layer energizers extending one of above or below a neutral plane of the rotor blade. The micro boundary layer energizers are shaped and positioned chordwise to delay separation of a boundary layer at a low angle of attack. A wind turbine including the blade assembly is additionally disclosed.

A method for designing and operating a wind power installation for generating electrical power from wind, wherein the wind power installation has an aerodynamic rotor with rotor blades of which the blade pitch angle can be adjusted, wherein the rotor blades are populated with a plurality of vortex generators between the rotor blade root and the rotor blade tip, characterized in that a radius position up to which the population with the vortex generators in the longitudinal direction of the respective rotor blade is carried out is determined depending on a sound power level to be set at a site of the wind power installation. A rotor blade of a wind power installation, to an associated wind power installation and to a wind farm.

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 method of retrofitting vortex generators on a wind turbine blade is disclosed, the wind turbine blade being mounted on a wind turbine hub and extending in a longitudinal direction and having a tip end and a root end, the wind turbine blade further comprising a profiled contour including a pressure side and a suction side, as well as a leading edge and a trailing edge with a chord having a chord length extending there between, the profiled contour, when being impacted by an incident airflow, generating a lift. The method comprises identifying a separation line on the suction side of the wind turbine blade, and mounting one or more vortex panels including a first vortex panel comprising at least one vortex generator on the suction side of the wind turbine blade between the separation line and the leading edge of the wind turbine blade.