Aerodynamic Blades for Silent Wind Turbines

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.

Source

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.

Source

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

Source

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.

Source

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.

Source

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.

Source

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.

Source

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.

Source

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.

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

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.

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 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.

Source

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.

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 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.

Source

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.

Source

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.

Source

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.

Source

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.

Source