CFD Analysis for Wind Turbine Noise Control

Adaptive trailing edge comb on wind turbine blades to reduce noise emissions. The trailing edge comb has serrations that can be adjusted in geometry and orientation based on parameters like air density, wind speed, and load. This allows optimizing the comb shape for specific operating conditions to reduce noise compared to fixed comb designs.

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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

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Method, equipment, and computer program for analyzing wind farm noise more accurately by considering the external environment impact on blade noise. It involves modeling and analyzing the entire wind farm instead of just individual blades. This allows accounting for factors like terrain, wind speed, vegetation that affect noise propagation. The method obtains virtual models and wind farm data for blades, determines the calculation domain, and solves numerically to obtain surface noise distribution. This improves blade noise analysis accuracy compared to single blade simulations.

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Representing rotating blade noise in a wind turbine using computer simulations to optimize blade design and reduce noise levels without expensive blade prototyping. The method involves importing 3D blade geometry, extracting blade parameters, computing airflow using blade momentum theory, and repeating simulations at multiple rotations to capture blade passage effects. The noise is calculated in the blade rotation frame of reference using scale-resolved CFD simulations covering a small fraction of a revolution. This allows statistical convergence by compensating for accurate noise signals over multiple rotations. The noise is then combined, corrected, and applied ground reflection/absorption/atmospheric absorption to represent rotating blade noise in the wind turbine.

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Computer method for accurately representing wind turbine blade noise using 2.5D simulations and blending to create realistic audio tracks. The method involves extracting blade geometry parameters and sectional flow data, simulating airflow past sections, computing noise spectra, blending spectra over a rotor revolution, synthesizing audio signals, and applying Doppler correction and absorption effects. This allows recovering blade noise over multiple revolutions by using 2.5D simulations covering a small portion of the rotor and blade.

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Optimal design method for wind turbine blades with high aerodynamic efficiency and low noise levels. It involves using a dual-objective optimization approach to find wind turbine blade airfoils with both high lift-to-drag ratios and low noise levels. The optimization targets are the maximum lift-to-drag ratio and total noise pressure level. Constraints ensure the airfoil meets other important aerodynamic requirements like lift coefficient, maximum lift coefficient, stall characteristics, and roughness stability.

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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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Noise reduction system for wind turbine blades using both passive and active techniques to significantly reduce trailing edge noise. The passive part is a serrated edge profile on the blade trailing edge. The active part is a sensor near the serrated edge that measures turbulent flow conditions. A control unit analyzes the sensor data to generate an anti-noise signal that is emitted by an actuator. The anti-noise signal is tailored to the serrated edge shape and flow conditions. Combining passive serrations with active flow sensing allows synergistic noise reduction beyond what each method alone can provide.

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A noise reduction system for wind turbine blades that combines passive serrated edges with active noise control. The system has sensors along the serrated edge to detect turbulent flow. A control unit uses the sensor signals to generate an anti-noise signal that is emitted by actuators. This active noise cancels out some of the blade noise. By combining passive serrations with active cancellation, the system aims to further reduce blade noise compared to just passive serrations. The sensors follow the serrated edge path to capture flow details. The control unit maps sensor signals to far field noise using a transfer function.

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Rapid method for predicting aerodynamic noise of wind turbines that provides a faster and more accurate way to calculate wind turbine noise compared to traditional methods. The method involves breaking down the wind turbine blade into elements along the span direction. It calculates the effective incoming wind speed and angle of attack for each element using blade element momentum theory and models. This data is then used to calculate the wall pressure spectrum and boundary layer parameters using a software tool. The airfoil trailing edge noise model and turbulent incoming flow noise are applied to each element to calculate the sound pressure level or power level. Superimposing the results from all elements gives the overall wind turbine noise.

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A noise reduction device and blade design for wind turbines that reduces aerodynamic noise generated during operation. The device has a body that attaches to the blade and a sawtooth unit with a sawtooth edge. The sawtooth angle is set to disrupt vortex formation on the blade surface. This breaks up vortex pairs, reduces vortex energy, and lowers blade surface pressure fluctuations to reduce noise. The body and sawtooth are angled to optimize vortex disruption.

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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 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.

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Optimizing the design of wind turbine blades to improve aerodynamic performance and reduce noise in low wind speed regions. The optimization method aims to achieve high lift-to-drag ratio and low noise levels for wind turbine blades operating in areas with low wind speeds. The optimization involves using a dual-objective, multi-condition optimization algorithm to find the optimal airfoil shape. The objectives are maximizing lift-to-drag ratio and minimizing total noise pressure level. Constraints include limiting the design lift coefficient, maximum lift coefficient, and stability parameters to ensure other important aerodynamic characteristics like stall behavior and sensitivity to roughness and turbulence.

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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.

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Reducing trailing edge noise in wind turbine blades by adding wedge-shaped elements at the blade tip to alter the flow separation and vortex shedding behind the blade trailing edge. The wedges reduce trailing edge noise without significantly impacting blade aerodynamics. They increase the trailing edge solid angle, moving the intersection point of pressure and suction flows closer to the trailing edge, which reduces the wake distance behind the trailing edge where vortex patterns form. The wedges can be attached as add-ons to existing blades or incorporated into new blades during manufacture.

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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.

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A method to design low-noise wind turbine blades by optimizing blade shape and load distribution to minimize noise while maintaining power output. The method involves using optimization algorithms to find the blade chord length and twist distribution that maximizes the blade power coefficient divided by the blade noise level. This balances power and noise tradeoffs. The optimization is constrained by blade root load limits to prevent excessive loads. The method incorporates turbulence noise modeling and blade load calculations in the optimization process.

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Reducing noise from wind turbine blades using curved tabs that modify the blade trailing edge shape. The tabs attach to the pressure and suction sides of the blade and have curved outer profiles that taper to the trailing edge. This modifies the blade's operational values at the trailing edge to reduce noise without permeability issues. The tabs are configured based on blade characteristics to provide desired values.

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Reducing aerodynamic noise from large-thickness blunt trailing edges on wind turbine blades by adding a serrated trailing edge. The serrated trailing edge, consisting of an upper and lower serrated part connected by a fixed plate, is fixed to the blunt trailing edge. It prevents the trailing edge shedding vortex that causes noise. The serration length is 0.1 times the airfoil chord length, and angles between the serrations and plate match. This breaks down the vortex into smaller ones. The gap between the serrations increases lift and reduces separation vortex noise.

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