Acoustic Blade Materials for Wind Turbines

A wind turbine blade with rapid noise reduction by using internal and external noise reduction components attached to the blade. The blade has a mounting plate on one side connected to the fan and a hub on the other side. Inside the blade near the hub is a fixed tooth-shaped component with an air guide groove in its outer surface. The tooth component has a base layer fixed to the blade outer surface and a sound-absorbing layer on the base layer outer surface. A smooth layer covers the sound-absorbing layer outer surface. Near the hub, there is also a fixed mounting block with a threaded fixing groove. Inside the hub, there is a threaded mounting hole and bolts to connect the mounting block and hub. This internal noise reduction component reduces blade vibration noise. Externally, the blade has a tooth-shaped component with an air guide groove on its outer surface. This external component reduces wind

Source

Low-frequency noise reduction wind turbine blade design that can adaptively adjust the blade shape based on wind direction to reduce noise. The blade has noise-reducing sawteeth, guide vanes, and a movable adjustment sawtooth. When the wind direction changes, a motor rotates a worm gear that drives the adjustment sawtooth along a track to change its orientation. This allows the blade to cut airflow differently based on wind direction to minimize noise.

Source

Low-noise wind turbine blade design that improves aerodynamic efficiency while reducing noise. The blade has an adjustable flap at the trailing edge made of acoustic metamaterial. The flap angle can be changed to increase lift at low wind speeds. The flap is also made of materials that absorb noise. By optimizing blade shape and adding noise-reducing flaps, the blade efficiency is increased while noise is reduced compared to traditional blades.

Source

Low-noise wind turbine blade with adjustable flaps at the trailing edge that can be moved to change the blade shape and improve lift and efficiency at low wind speeds. The flaps have sound-absorbing acoustic metamaterials to reduce noise radiation compared to fixed blades. The flaps can be moved using a drive mechanism to adjust the blade angle of attack. This allows optimizing blade shape for low wind starts and reducing noise pollution.

Source

Wind turbine blade design with internal damping elements to reduce noise and vibration during operation. The blades have cushioning elements extending from the interior surface to absorb impacts and vibrations. This prevents debris falling inside the blade from striking the interior surface and generating noise. The cushioning elements also reduce structural damage from internal debris impacts. The blades can further have acoustic dampening elements to absorb noise propagation through the blade interior.

Source

A wind turbine blade design with noise reducing features that improve noise reduction across a broad range of operating conditions while maintaining structural stability. The blade has a noise reducer with aligned spine members having sections of varying stiffness. The stiffer first section provides rigidity, followed by a more flexible second section. Adjacent spine members are connected at the rigid section but not at the flexible section. This configuration prevents noise generation due to blade flutter and vortex shedding over a wider range of airflow conditions compared to fixed stiffness designs.

Source

Noise reduction device for wind turbine blades that reduces trailing edge noise without increasing blade complexity. The device has a base part and multiple airflow modifying elements attached to the blade trailing edge. The elements are spaced apart and have a local height less than one-third the boundary layer thickness. This configuration breaks up the boundary layer to reduce separation-induced noise without affecting blade performance. The elements can be internal or external to the blade and can have varying lengths and shapes.

Source

A wind turbine blade design to reduce noise levels by incorporating a noise reduction structure on the leading edge. The structure has multiple layers: a small-hole honeycomb layer, a larger-pore honeycomb layer, and an acoustic wave reflection layer. The honeycomb layers absorb and scatter noise, while the reflection layer sends remaining noise back through the honeycombs for further absorption. This multi-layer setup converts, scatters, and absorbs noise to reduce overall blade noise levels.

Source

Noise reduction wind turbine blade design to mitigate the high noise levels generated by wind turbines. The blade has features to reduce noise from both blade vibrations and airflow disturbances. It uses a streamlined shape, internal sound absorbers, and a rotatable tail section with spoilers and a sound-absorbing wing. The spoilers rotate with wind direction to maintain angle. The streamlined shape reduces blade-airflow forces. The tail section absorbs vibrations and disperses airflow to prevent cyclones. The internal sound absorbers reduce blade vibration noise.

Source

Reducing noise generated by wind turbine blades by using serrated trailing edges with acoustically absorbent materials. The serrated portions reduce coherent scattering of noise, while the absorbent material reduces the reflected noise. This mitigates the noise emanating from the blades while in operation. The serrated trailing edges can be retrofitted onto existing blades to reduce noise without the need for noise reduced operation modes.

Source

A noise reducing wind turbine blade design that reduces blade noise without affecting aerodynamic performance. The blade has a noise reduction accessory along the trailing edge consisting of staggered comb/brush sets. The combs have alternating teeth inclined towards the blade tip and root. This changes the vortex shedding at the trailing edge to reduce low frequency noise. The tooth length is 2-40% of the local chord length.

Source

A wind turbine blade design with a graded impedance trailing edge to reduce noise. The blade has a gradual structure at the trailing edge instead of the conventional smooth or sawtooth trailing edges. A sound absorbing material with thickness grading is applied to the trailing edge. This graded impedance structure suppresses vibration of particles near the blade edge when high velocity incoming gas hits. This reduces diffraction of sound and noise. The gradual trailing edge design mitigates noise without affecting blade aerodynamics as much as brush, porous, or sawtooth trailing edges.

Source

A noise-reducing wind turbine blade design that aims to mitigate the high noise levels produced by rotating wind turbine blades. The blade has features like vortex generators, serrated tooth edges, and bent winglets to reduce noise at the blade leading and trailing edges. The vortex generators create turbulence that orders the airflow and reduces impact noise at the leading edge. The serrated teeth gradually taper in thickness from the inside out. The bent winglets transition smoothly between the blade root and leading edge, weakening vortex strength and noise at the trailing edge.

Source

Wind blade design that reduces noise and improves efficiency compared to conventional blades. The blade has embedded noise reduction components like rubber strips along its surface. The strips have different densities, angles, and lengths to optimize noise reduction. The strips are embedded at the root, mid-section, and tip to break up vortices as the blade rotates. The tip strips are bi-directional to match blade flow. Bottom strips further enhance top noise reduction. By dispersing vortices and offsetting vibrations, the blade reduces noise without negatively affecting efficiency or exceeding rotation limits.

Source

Reducing noise generated by wind turbine blades to improve efficiency and avoid restrictions by adding serrated trailing edges with acoustically absorbent materials. The serrations reduce coherent scattering of noise sources, while the absorbent material reduces noise reflection. This mitigates the noise emanating from wind turbine blades in motion.

Source

Rotor blade for wind turbines with a noise reduction device inside the boundary layer to significantly reduce trailing edge noise. The device is a porous cover inside the boundary layer that spans over part of the blade surface. The cover is positioned close to the blade at a predetermined distance. The cover is porous with an open area fraction between 30-95%. The cover's open structure scatters the boundary layer flow to move large turbulent structures away from the blade surface, reducing surface pressures and trailing edge noise.

Source

A rotor blade for wind turbines with a noise reduction device to mitigate blade-generated noise. The device has a porous cover spaced a distance from the blade surface. The cover connects to the blade with a means. The cover has an open area fraction between 30-95%, like a grid or flexible material. The cover alters the boundary layer flow over the blade to reduce turbulence and surface pressure. This reduces noise compared to a solid blade surface.

Source

A noise reduction device for wind turbine rotor blades that reduces strain transfer from the blade to the device and prevents delamination. The device has a low shear modulus adhesive layer between the blade and the noise reduction features. The low modulus adhesive allows the blade to flex without transmitting strain to the device. This prevents cracking or delamination of the device during blade flexing.

Source

Reducing noise from wind turbines by incorporating cellular materials into wind turbine blades to reduce noise via noise source reduction and / or noise attenuation and absorption. The cellular materials are tailored to affect the air flow over them in a controlled manner to mitigate turbulence and absorb scattered acoustic waves, thereby acting as acoustic linings. The cellular material sections of the blades are formed to reduce aerodynamic noise through noise reduction and absorption. This involves using cellular materials as part of the exposed surface of the wing, which reduces noise compared to using additional inserts or liners on a base wing construction. The cellular materials are chosen to provide structural integrity for wind turbine blade applications, but their surface characteristics are tailored to provide aeroacoustic advantages.

Source

An axial flow wind wheel with blades having a composite construction to reduce flow resistance and noise. The blades have a main body made of a first material and a covering layer made of a different material wrapped around part of the main body. This composite construction is used on the positive and/or negative pressure faces of the blades. The covering layer can be on just the positive or negative pressure face, or both. It reduces blade flow resistance, increases flow rate, and lowers noise compared to solid blades.

Source