Aerodynamic Blades for Silent Wind Turbines

Method to protect wind turbine blades from erosion while reducing drag and noise compared to traditional protective films. The method involves forming a groove on the leading edge of the blade where a thin film will be applied. The groove delimits a region of the blade from the rest. The thin film is then applied to the grooved region and pressed into the groove. This prevents the film edge from lifting due to airflow, reducing delamination. The groove also reduces drag and noise compared to a step edge without the film.

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Wind turbine blade design to reduce edgewise vibrations and fatigue loads without adding weight or complexity. The blade has a unique airfoil shape with a bump section near the trailing edge. The bump section has a thicker pressure side compared to the rest of the blade, causing the blade to flex less in edgewise vibrations. This reduces fatigue loads and noise compared to conventional blades. The bump section can be a separate airfoil section or integrated into the blade.

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Optimizing wind turbine rotor blades for low air density sites to maintain performance and reduce noise. The optimization involves adding sound protection bristles on the blade tips. The bristle density is increased compared to design when the air density is lower. This compensates for reduced lift due to lower air density. The bristle density factor is normalized based on bristle count, diameter, and span.

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Blade designs for propellers that provide lower global torque, higher efficiency, and lower noise compared to classical propeller designs. The blade has three sections: a high lift section near the root, a transition section, and a lower lift section near the tip. This configuration allows optimizing the blade loading and airfoil shapes along the span to reduce torque, improve efficiency, and lower noise compared to constant lift blades.

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ABSTRACT To enhance the performance of wind turbines, this study investigates integration two energy harvesting systems. An optimal turbine configuration has been identified by using dual rotor (DRWT) technology with a novel blade design known as humpback blade, which is inspired fins whales. This features tubercles and ridges along leading edge that extend over last third blade's length. The innovative lowered nominal angle attack in comparison to conventional blades, led significant boost lift notable reduction drag forces. enhancement lifttodrag ratio enabled more efficient rotation at lower speeds. Furthermore, single turbines fitted these blades showed improved extraction decreased turbulence intensity behind rotor, making them especially effective DRWT setups. results validated benefits systems, where new enhanced both upwind downwind positions, resulting higher overall output than standard blades. As result, different configurations have tested examined. proposed position resulted increase ratio. Similarly, employing . These enhancements lead greater from DRWTs compared ... Read More

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Studies that involve mitigating aerodynamic noise in rotating components such as rotors of wind turbines or propellers Unmanned Aerial Vehicles have gained immense interest the research community over last few years. The present study explores mitigation potential passive compliant coatings through Computational Aeroacoustics Analysis (CAA) and experimentation tunnel testing. CAA was performed on a flat plate for chord-based Reynolds number Re c = 460,000 using SST k- Improved Delayed Detached Eddy Simulation Ffowcs Williams Hawkings acoustic analogy. Trailing edge (TE) accurately predicted from 750 to 7000 Hz. Noise results were compared with cases where different material properties are applied onto plate. It observed coating-1 (Dow Corning Silastic S-2) may increase TE by 10 15 dB/Hz throughout frequency range interest, an Overall Sound Pressure Level (OASPL) 2.89 dB. Whereas coating-2 Sylgard 184) shifted energy content lower reduced 2 4 600 1575 Additionally, it resulted 1.85 dB reduction OASPL, thus demonstrating choice coating materials viscoelastic plays crucial role... Read More

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Abstract Owls have evolved remarkable adaptations for near-silent flight, offering a compelling model understanding aerodynamic noise reduction. Their morphological specializationssuch as leading-edge serrations, trailing-edge fringes, and velvety wing surfacesprovide crucial insights into bioinspired solutions various engineering applications. However, the exact aeroacoustic mechanisms underlying these remain only partially understood. This review provides comprehensive synthesis of key biomechanisms associated with silent including both historical perspectives latest experimental computational findings. We also systematically classify analyze current biomimetic applications in contextsincluding aircraft reduction, wind turbine blade optimization, other industrial implementationsthereby establishing clear mechanistic link between fundamental principles real-world solutions. Finally, we discuss challenges future directions owl-inspired aeroacoustics, emphasizing intergration adaptations, flexibility, flight kinematics. By bridging biological innovation, this work undersco... Read More

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Reducing trailing edge noise of an airfoil by using channels that allow fluid to flow from higher pressure near the leading edge to lower pressure near the trailing edge. The channels separate the pressure and suction sides at the trailing edge, reducing the momentum difference and vortex shedding frequency compared to conventional airfoils. Channels have inlets on the leading edge and outlets near the trailing edge.

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ABSTRACT As the demand for power increases, installing smallscale wind turbines can be an alternative solution. However, main challenge their implementation is aerodynamic noise. With a view to minimizing noise, this study focuses on performance investigation of horizontalaxis turbine with NACA 4412 blades inspired by humpback whale flippers (trailingedge tubercles and inward dimples). Wind conventional modified biomimetic were tested in six angles attack (AOAs) between speeds 4 11 m/s. The cut speed was less bladed delivered higher rotational than one. equipped blade produced output 14.98 W at 8.8 m/s, surpassing 13.72 W, generated turbine. At 30 AOA, coefficient 56.43% higher, sound pressure level 2.99% lower. Hence, redesigned design improves efficiency results noise reduction, potentially enabling more sustainable energy options.

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Wind turbine blade design to reduce aerodynamic noise without impacting power generation. The blades have a specific solidity distribution along the blade radius that allows lower tip speeds without reducing lift force. The blade geometry is optimized to reduce noise at high tip speeds, which are common in large wind turbines. The specific solidity at 70%, 80%, and 90% of the blade radius must meet certain thresholds to achieve the noise reduction. This allows lower tip speeds for less noise without reducing power output.

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Abstract As the noise reduction induced by owl trailing-edge serrated design of wind turbine blade during operation has gradually become industrial consensus, corresponding effect aerodynamic performance on still not been investigated systematically. In present study, two types bionic blades (B-A and B-B) with different serration lengths have designed based NREL phase VI (W-B). The flow control mechanism under incoming speeds studied through numerical simulation approach. findings indicate that, turbines rotation speed held constant at 72 r/min, pressure difference between suction surfaces rises progressively as increases from 7m/s to 13m/s. This increase in difference, turn, leads a rise torque exerted blade. is faster than 13m/s, velocity gradient base higher that W-B, which promotes larger training-edge serrations size, more obvious improvement

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Bionic wind turbine blade design that reduces noise without sacrificing aerodynamic performance. The blade has a non-smooth leading edge and a curved sawtooth trailing edge, especially at the middle to end sections of the blade. This bionic shape inspired by owl wings and feathers aims to significantly reduce aerodynamic noise generated by wind turbine blades while maintaining aerodynamic efficiency. The non-smooth leading edge and curved serrated trailing edge are applied to the noise source areas near the blade mid-span.

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Blade design for wind turbine blades that reduces noise compared to conventional blade shapes. The blade has a profile inspired by the wings of long-eared cuckoos. The blade has a lower convex curve and an upper concave curve. This shape guides airflow into the concave section which throws it out, reducing unstable circulation and noise. The cuckoo wing-inspired blade design was found to significantly reduce noise compared to conventional blade shapes through numerical simulation and experimental testing.

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Wind turbine blade design with sawtooth panels at the trailing edge to improve power generation and reduce noise. The blade has a main body and multiple sawtooth panels attached to the trailing edge. The sawtooth panels increase lift by creating vortices and delaying airflow separation compared to a smooth trailing edge. This provides higher torque and annual power generation. The sawtooth panels are bonded to the blade body rather than fastened to avoid impacting structural stability and noise.

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Reducing noise from wind turbines by adding a dorsal fin-like structure at the blade tips. The fin extends vertically from the blade tip and has a curved shape that follows the blade profile. The fin reduces noise by breaking up the vortex shedding that occurs at the blade tips. This vortex shedding is a major source of noise from wind turbines. The fin disrupts the vortex shedding pattern, which reduces the noise emitted by the turbine. The curved shape of the fin matches the blade profile to maintain aerodynamic efficiency while still reducing noise.

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Bionic wind turbine blade design to reduce noise and improve durability. The blades have a unique shape with curved sections joined at tapered ends. The curved sections form an arc transition between larger and smaller planes. Multiple curved sections are stacked perpendicularly to form the blade. Wings are attached to the blade surface. This bionic blade shape reduces noise by reducing pressure pulsations on the blade surface. The tapered ends and curved sections also improve durability by reducing stress concentrations. The wings further reduce noise by altering the flow over the blade.

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Bionic blade design for wind turbines that reduces aerodynamic noise compared to conventional blades. The blade has a non-smooth leading edge shape with features like sawtooths, bumps, and concave points. This bionic leading edge structure helps rectify the airflow velocity distribution on the blade surface, reducing pressure pulsations and separations that cause noise. The irregular edge induces vortex generation to control separation and stability. It aims to uniformize airflow over the blade and mitigate wake turbulence at the trailing edge.

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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.

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Wind turbine blade design to reduce noise at the trailing edge. The blade has a noise reducing portion near the trailing edge with multiple acoustic resonators. Each resonator has an opening in the blade surface and a cavity with a length between the opening and bottom. The resonators absorb sound waves and mitigate trailing edge noise. The cavity length can be optimized for different frequencies. The resonators can have partition walls to divide the cavity into multiple parts. Some resonators can be covered with permeable layers. The resonators can be curved or slanted. The blade can have serrations with resonators.

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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.

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Wind turbine blade with trailing edge serrations that reduce noise and improve aerodynamics. The blade has serrations along the trailing edge with flow alignment vanes positioned apart from the notional line connecting the serration base to apex. The vanes align flow towards the notional line to reduce trailing edge vortices and noise. The serrations protrude into the wake, continuing the flow alignment effect after the air leaves the serrated surface. The vanes are preferably plastic to match the blade material. The blade can have a profiled contour with a bead between the trailing edge and leading edge. The serrated panel can attach to the blade edge.

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High speed wind turbine blade design to reduce noise levels when the turbine rotates at high speed. The blade shape is optimized with swept and unhedral curves on the leading and trailing edges to create a low noise airflow around the blade tips. This reduces noise compared to conventional blade shapes by naturally guiding the airflow along the curved surfaces instead of causing turbulence and noise impacts. The swept and unhedral curves aim to minimize low frequency noise absorption and maximize high frequency noise dissipation.

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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.

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A low-speed, low-noise wind turbine blade design for urban areas with low rotor speeds to mitigate noise and vibration issues. The blade has a maximum tip speed of 100 km/h or less, regardless of wind speed. The blade shape has a covered metal suction panel on one side, rather than fully occupying the side. This reduces drag and noise compared to fully enclosed blades. The covered metal structure allows fossil fragments inside to reduce noise further. The reduced tip speed and unique blade shape enable low-noise, low-speed urban wind power generation.

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Retrofit system for a wind turbine blade that reduces noise generated by wind turbine blades. The system includes a trailing edge, a mounting structure, and at least one serrated portion extending at least partially along the mounting structure.

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Wind turbine blade design with a non-truncated, flow-permeable add-on attached to the sharp trailing edge to mitigate noise, prevent clogging, improve lift, and promote flow reattachment. The add-on is flow-permeable and attaches to the pressure and/or suction side of the trailing edge. This improves noise reduction by mitigating broadband and tonal noise components, prevents clogging by allowing debris passage, improves lift generation at high incidence flow, and promotes flow reattachment.

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Noise reduction structure for wind turbine blades that reduces blade noise without sacrificing strength. The structure has a series of teeth along the blade trailing edge. The teeth are connected by a reinforcement portion. The teeth length increases from root to tip. This shape changes the blade trailing edge profile to avoid shedding vortices that cause noise. The reinforcement divides the teeth into sections. The triangular tooth edge enhances noise reduction. The teeth structure reduces broadband scattered noise compared to sharp edges.

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Wind turbine blade tip design with double winglets to improve aerodynamic performance and reduce noise. The blade tip has a Y-shaped winglet with a curved-swept leading edge and concave trailing edge. The winglet has an air termination device connected to the lightning arrester. This design reduces tip loss, improves blade efficiency, and changes airflow distribution to reduce noise compared to conventional blade tips.

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Wind turbine blade with noise-reducing sawtooth trailing edge attachment to mitigate blade aerodynamic noise. The attachment has a bonding section, flap section, and sawtooth section. The flap and sawtooth segments are solid structures. Multiple attachments are installed along the blade trailing edge. This design provides consistent noise reduction in any wind direction compared to conventional sawtooth edges. The flap section prevents flutter and reduces loads. The solid segments avoid damage from blade impacts.

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Wavy leading edge winglet for the tip of a wind turbine blade that improves blade efficiency, reduces noise, and mitigates tip vortexes. The winglet has a wavy front edge starting at a plane near the blade tip. The wavy leading edge extends along the span from that starting plane. This wave-shaped front edge transitions smoothly to the blade's trailing edge. It changes the airflow direction near the tip, reducing induced drag and tip vortexes compared to a straight leading edge.

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Bionic leading edge wind power blade design to improve aerodynamics and reduce noise compared to traditional blades. The blade has a sinusoidally varying convex leading edge shape that is periodically distributed along the blade. This bionic leading edge geometry promotes boundary layer attachment, reduces separation, and improves performance over the entire blade span. The convex shape is optimized through testing and design to balance aerodynamics and noise reduction.

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A wind turbine blade design with integrated noise reduction that addresses the limitations of prior art noise reducers. The blade has a noise reducer attached near the trailing edge. The noise reducer has a base plate with openings. The noise reduction devices extend from the base line and are arranged symmetrically on opposite sides of the base line. This allows accurate and efficient positioning of the noise reduction devices on the blade without additional mounting hardware. The blade itself defines the blade angle axis.

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Wind turbine blade design with a porous media on the trailing edge to reduce noise without sacrificing aerodynamic performance. The porous media allows internal flow circulation and increases boundary layer thickness compared to a solid trailing edge. This reduces noise sources and pressure pulsations in the trailing edge area. The porous media can be metallic or non-metallic. The porous section length is limited to avoid excessive aerodynamic losses. The porous media increases surface roughness and flow complexity, but only at the trailing edge.

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A wind turbine blade tip winglet design that improves blade performance, reduces drag, and noise compared to conventional winglets. The winglet has a wavy leading edge starting from a plane along the blade span. This transition helps mitigate tip vortex issues by changing the airflow near the blade tip. The smooth trailing edge and coinciding trailing edges with the blade ensure compatibility. The wavy leading edge is prepared by modifying an existing winglet airfoil starting from a plane along the blade span.

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Wind turbine blade with asymmetric winglets to reduce induced drag and tip vortices for higher efficiency and lower noise compared to conventional blades. The blade has a main winglet facing the pressure side and an auxiliary winglet facing the suction side at the tip. This asymmetric winglet configuration disrupts the flow field at the tip to decrease induced drag and disperse tip vortices.

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Wind turbine blade and attachment device with sawtooth serrations along the trailing edge that prevent tonal noise without affecting aerodynamics. The serrations have peaks and valleys that alternately extend into the blade thickness. The cross section along the blade cord remains a blade shape throughout, avoiding steep discontinuities. This sawtooth profile prevents alternating vortices and tonal noise compared to flat serrations. The wind turbine wing attachment device has sawtooth serrations on the first surface of the wing trailing edge that connect to wall surfaces on the blade.

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Rotor blade for a wind turbine that decreases the noise emission. The blade has a trailing edge for a rotor blade, a rotor blade trailing edge and to a wind turbine. The blade has a rotor blade tip, a rotor blade root, a suction side, a pressure side, a rotor blade length, a profile depth and a pitch axis of rotation. The rotor blade has a trailing edge with a serrated delimiting line.

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Blade design for wind turbines that reduces noise levels compared to conventional blades. The blade has serrated teeth on the trailing edge near the tip. The teeth are angled towards the blade tip direction. This configuration reduces aerodynamic noise by breaking up the airflow and preventing large pressure differences that can cause noise. The angled teeth align with the flow direction at that location. This optimizes noise reduction compared to parallel serrations.

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Wind turbine blade design to reduce trailing edge noise by adding fins adjacent to the serrated trailing edge. The fins project from the blade surface and extend beyond the serrations. This configuration dissipates more vortex energy and reduces scattering compared to serrations alone. The fins have greater length than the serrations and their trailing ends lie between the serration edges.

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A wind turbine blade design to reduce noise generated by wind turbines. The blade has a noise reduction mechanism at the rear tip. It consists of an extension joint, flap, and noise reduction tooth. The flap and tooth decompose the boundary layer of airflow to reduce noise. The flap connects to the extension joint at the blade tip. The tooth extends from the flap. This design reduces trailing edge noise of the blade.

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Wind turbine blade design to reduce noise and improve durability. The blade has a sound-absorbing cotton covering on the outside, an impeller drum at the top, a bearing inside, brushes on the blade trailing edge, and a support plate attaching the blade to the tower. The bearing and blade ends are sleeved, the bearing inner wall is longer, and the blade end has bumps. The support plate connects the blade and bearing walls. The brushes, bumps, and sleeve contacts prevent blade separation. The cotton reduces noise. The support plate strengthens the blade and adjusts blade shape.

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Reducing tonality in wind turbine blades to improve noise performance by strategically thickening the blade near the trailing edge. This involves creating a local maximum in thickness at the blade tip end to mask tonal frequencies. The thickening is done on the suction or pressure side or both, and extends between 20-50% of the blade depth. This masking effect makes tonal frequencies less noticeable by blending them into the broader noise spectrum.

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Reducing tonality in wind turbine noise by thickening the blade trailing edge in a specific area. The blade has a local maximum thickness at the trailing edge between root and tip. This increases the blade's acoustic absorption in that frequency range, masking tonality peaks and reducing overall perceived noise annoyance.

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Environmentally friendly low-noise wind power generator that reduces noise during operation compared to conventional wind turbines. The noise reduction is achieved by modifying the wind wheel design to prevent periodic low-frequency sounds and sealing the generator and gearbox to reduce noise transmission. The wind wheel has a deflector with blades and grooves that prevent periodic airflow patterns. The blades have preformed grooves with limit rods and movable panels that prevent airflow stall. The movable panels have countersunk grooves with buffer pads to absorb impacts. The generator and gearbox are sealed inside the unit housing to prevent noise transmission. This reduces low-frequency noise propagating outward during operation, making the wind turbines quieter and more suitable for closer placement near people.

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A method for designing low-noise wind turbine blades that balances power output and noise levels. The method involves optimizing chord length and twist distribution to increase power while reducing blade noise. The optimization uses a blade noise model, turbulence model, and load constraints. It calculates noise and power for each blade section, then iteratively adjusts chord and twist to maximize power-to-noise ratio.

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Noise reducers for wind turbine rotor blades that reduce noise generated by the blades without increasing high-frequency noise. The noise reducers are cambered serrations that eliminate the sharp edges of conventional serrations to address noise issues. The cambered serrations have suction and pressure sides with curved shapes that vary along the serration length. This eliminates side edge vortices and scattering of pressure fluctuations that generate noise. The cambered shape also manipulates the flow field around the serrations for better low frequency noise reduction. The serrations extend beyond the blade trailing edge.

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Rotor blade design for wind turbines with reduced noise and improved aerodynamics. The blades have a flat trailing edge instead of the usual curved shape. This reduces blade size and transport costs. However, flatback blades can cause noise issues. To mitigate this, the blade has a stepped trailing edge element that extends the flat section. This avoids the aeroacoustic issues of a blunt trailing edge while keeping the size benefit. The stepped element can have multiple sections perpendicular to the flat edge.

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Blade design for wind turbine blades that reduces noise compared to conventional blade shapes. The blade has a lower convex surface followed by an upper concave surface. This configuration guides the airflow to avoid unstable circulation and throws it out, reducing noise. The convex lower surface guides the airflow into the concave upper surface, which throws it out. This prevents airflow instability and improves airflow efficiency.

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Rotor blade assembly for a wind turbine that reduces laminar boundary layer instability noise. The 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.

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Noise reducers for wind turbine rotor blades having serrated edges to mitigate noise generation. The noise reducers have serrations with features that reduce vortices and noise compared to conventional serrated edges. The serrations have bases that attach to the blade trailing edge and side edges that extend out of the base plane. This configuration reduces vortices formed at the serration edges that can generate noise. The base plane can be parallel to the blade surface or angled slightly. The side edge extension prevents vortex formation and noise generation at the serration edges.

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