A method (100,200) of reducing a noise emitted by at least one of rotor blades of a wind turbine and a tower of the wind turbine, the wind turbine further including a drivetrain connected to the rotor blades via a hub of the wind turbine, the drivetrain comprising a gearbox, a generator, and a high speed shaft; wherein the gearbox and the generator are coupled by the high speed shaft; the method (100,200) including determining (110,210) an occurrence of the noise, and applying (120,230) a braking torque upon determining the noise, wherein the braking torque is applied to the high speed shaft during normal operation of the wind turbine to reduce the noise.

A noise-reduction device for a wind turbine and the wind turbine applied thereof are introduced. The noise-reduction device has a body. The body has a connection portion and a spoiler. The connection portion is concavely disposed on one side of the body and corresponds in shape to the wind turbine's blade so as to be fixed to a confronting edge of the wind turbine blade. The spoiler is disposed on the opposing side of the body. As soon as the wind turbine blade is driven by wind, the spoiler stirs air and guides the air across two sides thereof. When guided by the spoiler, airflows turn into vortexes on the wind turbine blade; hence, the chance that the wind turbine will stall and generate noise is greatly reduced.

A wind turbine noise suppression system can include a sound absorbing batting and a fabric sheet within a column of the wind turbine. The sheet can hang within the column whereas the batting can be placed in at least a bottom and top region. A vibration isolation pad at the top of the column can mitigate a megaphone effect. The pad can be combined with an isolation washer. The pad can be less than a half inch thick, whereas the isolation washer can be less than a quarter inch thick. A sound curtain can be installed at a base of the column to suppress bell resonance. The system can, for example, reduce wind turbine noise up to ninety percent.

A rotor blade of a wind turbine, the rotor blade including a winglet and a lightning protection system with at least one lightning receptor is provided. The lightning receptor is located at the tip section of the rotor blade. Additionally, the rotor blade includes at least one lightning diverter containing an electrically conductive material, wherein the lightning diverter terminates at the lightning receptor and is located at least partially on the surface of the winglet.

A method of masking tonal noise from a wind turbine. The wind turbine has a noise generator and a rotor-nacelle-assembly (RNA). The RNA comprises a nacelle and a rotor configured to rotate about a rotor axis with a horizontal projection. The method comprises: feeding a drive signal into the noise generator so that the noise generator emits directional masking noise, wherein the directional masking noise at least partially masks tonal noise from the wind turbine and points in a masking direction with a horizontal projection. The horizontal projection of the masking direction points away from the horizontal projection of the rotor axis.

A rotor blade assembly for a wind turbine. The rotor blade assembly includes a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. The rotor blade assembly also includes at least one noise reducer secured at the trailing edge. The noise reducer(s) includes at least one serration having a base portion and at least one side edge feature extending from the base portion. Further, the base portion extends along a first plane. The side edge feature(s) extends out of the first plane so as to reduce vortices generated by the serration(s).

A rotor blade assembly for a wind turbine includes a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. The rotor blade assembly also includes at least one noise reducer adjacent to the trailing edge. The noise reducer(s) includes at least one serration extending beyond the trailing edge in a chord-wise direction of the rotor blade. The serration(s) also includes a suction side surface and a pressure side surface. The suction side surface defines a first radius of curvature in the chord-wise direction and the pressure side surface defines a second radius of curvature in the chord-wise direction. Further, the first radius of curvature may be larger than the second radius of curvature such that the suction side surface is flatter than the pressure side surface or vice versa.

A wind turbine includes at least one blade having a pressure side, a suction side, a leading edge, and a trailing edge that define an airfoil-shaped profile. The suction side and/or the pressure side has a morphable region. The wind turbine also includes a control system configured to activate the morphable region to alter the airfoil-shaped profile and reduce negative lift generated by the blade when the blade is oriented at a negative lift angle.

A method for modifying a sound emission of a wind power installation, wherein the wind power installation comprises a nacelle and a generator with a rotor which is adjustable in terms of its rotational speed, and the rotor has at least one rotor blade, the generator produces sound with at least one characteristic generator sound frequency which depends on the rotor rotational speed, the wind power installation has at least one fan for cooling the nacelle and/or generator, the at least one fan is adjustable in terms of a fan rotational speed, wherein the at least one fan produces sound with a characteristic fan sound frequency which depends on the fan rotational speed, and the fan rotational speed of the at least one fan is set in such a way on the basis of the rotor rotational speed that the fan sound frequency deviates from the at least one generator sound frequency. Tonal sounds in wind power installations, or the perception thereof, are intended to be reduced in particular.

A rotor blade assembly for a wind turbine includes a rotor blade having surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge extending between a blade tip and a blade root. The rotor blade assembly also includes at least one noise reducer adjacent to the trailing edge. The noise reducer(s) includes at least one serration extending beyond the trailing edge in a chord-wise direction of the rotor blade. The serration(s) also includes a suction side surface and a pressure side surface. The suction side surface defines a first radius of curvature in the chord-wise direction and the pressure side surface defines a second radius of curvature in the chord-wise direction. Further, the first radius of curvature may be larger than the second radius of curvature such that the suction side surface is flatter than the pressure side surface or vice versa.