Drag Reduction for Wind Turbine Blades

Improving wind power plant efficiency is crucial due to the increasing demand for renewable energy. This study analyzes aerodynamic characteristics of a equipped with two combined blades that integrate fixed and rotating cylinders. The object model designed optimize airflow direction enhance lift. methodology involves numerical modeling using Ansys Fluent software package, as well experimental testing under laboratory conditions. main results show when air-flow velocity increases from 3 12 m/s, thrust force rises 0.5 N 3.85 N. Comparative analysis minimum maximum pressure on blade surfaces demonstrates strong correlation between rotational speed elevated differentials: pmax approximately 0.4 Pa 0.7 Pa, while pmin about 0.15 Pa. coefficient decreases 1.45 1.05 Reynolds number (Re) increases, indicating improved during transition turbulent flow. A comparative data reveals deviation no more than 5%, confirming models reliability soundness research methodology. conclusions indicate employing can by 810% compared traditional designs. improvement may foster development efficient stab... Read More

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Wet lay-up and vacuum-assisted resin transfer molding have been considered as the most popular cost-effective manufacturing processes of E-glass fiber reinforced epoxy-based laminated composite, especially in wind turbine blade industry. This study compares fatigue behavior GFRP composites manufactured via wet processes. Vacuum-assisted samples exhibited 85% longer life at a stress level 0.4 ultimate tensile strength compared to samples. The average was 50% higher, with improved resistance due enhanced fiber-matrix bonding. Scanning electron microscopy fracture analysis revealed fiber/matrix bonding fatigued samples, contributing performance. These findings provide critical insights for material selection optimization. results indicate that sustain 4.5 more load cycles lower levels, demonstrating superior performance blades.

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In this study, the aerodynamic performance of different wind turbine blades including FX 63-137, NACA 6415, 63-415 has been investigated. XFLR5 employed to analyze blade at Reynolds numbers ranging from 1.5x105 1x106 and low angles attack (00200). The lift (CL), drag(CD), pitch moment (CM) coefficients, lift/drag coefficient ratio (CL/CD) have evaluated. Numerical coefficients obtained using literature beeen compared it found that they compatible with each other. According numerical analyzes, highest coefficient-to-drag ratio, as called efficiency, was 109.14 FX63-137 Re number 1x106, lowest 2.63 blade. Also, maximum profile 104.28, while for NACA6415 102.11 1x106. analysis results show increases increase in angle up stall angle, then begins decrease all studied blades.

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In this paper, the aerodynamic performance of an improved hybrid vertical-axis wind turbine is investigated, and at high tipspeed ratios significantly enhanced by adding a spoiler end inner rotor. The design increases average torque coefficient 7.4% peak power 32.4%, which effectively solves problem loss due to negative rotor in conventional TSR; improves outer wake region optimizing airflow distribution, reducing counter-pressure differential, lowering drag same time attenuating turbulence intensity. study verifies validity through 2D CFD simulation, provides new idea for optimization turbines, especially suitable low speed complex terrain environments, great significance promotion renewable energy technology development.

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Current wind turbine optimization studies primarily employ either the Blade Element Method (BEM) or Computational Fluid Dynamics (CFD) to evaluate rotor aerodynamic performance. While BEM remains widely used due its simplicity and low computational cost, it depends heavily on empirical correction factors that can limit accuracy in complex flow conditions. Conversely, although CFD provides highly accurate results by solving Navier-Stokes equations, is computationally expensive often impractical for large-scale parametric studies. Vortex methodsparticularly prescribed wake methodoffer a promising compromise, balancing efficiency with acceptable levels of accuracy. In present study, we propose novel blade model derived through multi-objective blade's geometric parameters, specifically chord distribution twist angle. The performance optimized evaluated using an enhanced model. Aerodynamic noise estimated Brooks method, while production cost calculated Zudongs resulting design demonstrates 3% increase power output, 0.02 dB reduction emissions, marginal 1.2% cost. These finding... Read More

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ABSTRACT We develop a torquepitch control framework using deep reinforcement learning for wind turbines to optimize the generation of turbine energy while minimizing operational noise. employ double Qlearning, coupled blade element momentum solver, enable precise over parameters. In addition momentum, we use acoustic model Brooks Pope and Marcolini. Through training with simple winds, agent learns optimal policies that allow efficient complex turbulent winds. Our experiments demonstrate can find optimals at Pareto front when maximizing addition, adaptability changing conditions underscores its efficacy realworld applications. validate methodology SWT2.393 rated power 2.3 MW. compare classic controls show they are comparable noise emissions not taken into account. When including maximum limit 45 dBA in produced (100m downwind turbine), extracted yearly decreases by 22%. The is flexible allows easy tuning objectives constraints through reward definitions, resulting multiobjective optimization control. general, our findings highlight potential RLbased strategies imp... Read More

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An airfoil is the cross-sectional shape of a wing, blade, or sail, designed to generate aerodynamic forces as it moves through air. When interacting with airflow, an generates lift and drag forces. To standardize design, National Advisory Committee for Aeronautics (NACA) developed various families, extensive studies focused primarily on 4-digit series. However, limited attention has been given behaviour 5-digit This study assesses performance NACA 23012, airfoil, under varying Reynolds numbers angles attack establish its suitability high wind turbind. Computational Fluid Dynamics (CFD) simulations were conducted at (AoA) 8, 12, 16, 20, 24, 3.0106, 6.0106, 8.8106. The objective was identify conditions that yield optimal in terms lift-to-drag ratio (L/D), coefficient (CL), (CD). Results showed increase increasing AoA up critical range between 12 beyond which flow separation stall effects reduced efficiency. observed 8 angle number 8.8106, where relatively low resulted favourable ratio. A linear regression analysis revealed insignificant variation CFD results stand... Read More

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Riblets are a well-known passive drag reduction technique with the potential for as much $9\, \%$ in frictional force laboratory settings, and proven benefits large-scale aircraft. However, less information is available on applicability of these textures smaller air/waterborne vehicles where assumptions such periodicity and/or asymptotic nature boundary layer (BL) no longer apply shape bodies can give rise to moderate levels pressure drag. Here, we explore effect riblets both sides finite-size foil consisting streamlined leading edge flat body Reynolds number range $12\,200$ $24\,200$ . We use high-resolution two-dimensional, two-component particle image velocimetry, double illumination consecutive-overlapping imaging capture velocity field BL far field. find local profiles shear stress distribution, well components show possibility achieving record maximum cumulative up $6.5\, present intertwined relationship between distribution spanwise-averaged characteristics around body, how parameters work together or against each other enhancing diminishing drag-reducing ability entirety ... Read More

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Reducing skin friction of surfaces using passive phononic subsurfaces that alter fluid flow characteristics to delay boundary layer transition from laminar to turbulent. The subsurfaces are multi-input, multi-output phononic structures with interfaces exposed to flow pressure/velocity gradients. They contain phononic crystals or resonant metamaterials that passively change flow phase and amplitude in response to flow forces. By altering flow frequencies, the subsurfaces can reduce turbulence instability growth. The phononic subsurfaces can be integrated into surfaces like airfoils to passively delay boundary layer transition and reduce drag.

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This study investigates the optimum aerodynamic performance of small-scale Horizontal Axis Wind Turbines (HAWTs) utilizing a mixed-airfoil blade design. The QBlade software was employed for selection best performing airfoils based on lift-to-drag ratio and range operational performance. Additionally, Blade Element Momentum (BEM) theory deployed analysis blade's design Finally, in Computational Fluid Dynamics (CFD), SST k- turbulent model also applied better analysis. key findings demonstrated that optimal including SG6040 (root), NACA 4711 (middle), SG6043 (tip), were chosen their superior structural integrity. Furthermore, designed achieved power coefficients 0.454 (BEM), 0.432 (QBlade), 0.395 (CFD) at Tip Speed Ratio (TSR) 5.5, which are greater than conventional single-airfoil designs. It concluded configurations significantly enhance efficiency small scale wind turbines, future research torque control mechanism integration is essential to further optimize energy capture.

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Active lift modifying device for wind turbine rotor blades to reduce lift and increase drag during certain conditions. The device has fluid jets on the suction or pressure side of the blade that generate a curtain separating the airflow. Compressed fluid is supplied to the jets to create the curtain, reducing lift and increasing drag compared to normal blade operation. This can be useful in situations like shutdowns, extreme gusts, or turbulence when lower lift loads are desired. The device can be deactivated during normal operation to maintain high lift. The curtain size and location can be adjusted using separate compressed fluid sources or valves.

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This study investigates the applicability of modified Reynolds stress limiter to improve accuracy two-dimensional computational simulations Savonius wind turbine. The modification is applied shear transport k model by incorporating strength parameters a1 and Clim. numerical methods using User Define Function were first validated before being turbine under various flow tip speed ratios (TSRs) configurations. results show that increasing (or decreasing Clim) strengthens turbulent quantities, vortex zone inside blade, thin strain layer. These effects delay attachment separation along reduce positive pressure force on turbine, accelerate decay in wake, minimize deviation. Based analysis, a new set (a1 = 0.45 Clim 0.67) recommended, especially for high-fidelity at high TSRs, which standard turbulence models typically overestimate. finding essential accurately designing high-efficiency shows potential applications urban offshore environments.

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This project focuses on the optimization of a custom airfoil by systematically analyzing effects camber percentage (2% 6%), position (1 6), and angle attack (6) while maintaining fixed thickness 12%. The primary objective is to maximize lift- to-drag ratio (L/D) enhance aerodynamic efficiency stability. A parametric investigation was conducted using both unilabiate bivariate analyses evaluate influence individual combined parameters performance. To achieve this, XFOIL, high- fidelity analysis tool, integrated with MATLAB for automated batch processing, enabling efficient computation lift coefficient (C), drag (C), corresponding L/D ratios. study revealed that variations in its significantly affect characteristics, offering critical insights design optimized airfoils applicable aircraft wings, UAVs, wind turbine blades. In addition analysis, this explores advanced techniques, focus evolutionary algorithms such as Genetic Algorithm (GA). GA framework employed search configurations yield optimal ratios iteratively refining candidate solutions based selection, crossover, m... Read More

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Wind turbine blade design with offset flexible and stiff add-on elements to improve aerodynamics while facilitating handling. The blade has a mix of flexible and stiff add-on elements arranged offset in span and chord directions. The flexible elements are made of elastic materials like rubber to absorb impacts during handling. The stiff elements are made of stiffer materials. This allows protecting the flexible elements during blade handling without constraining their placement. The offset arrangement of flexible and stiff elements also improves blade aerodynamics by reducing drag and increasing lift compared to using all flexible or all stiff add-ons.

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Vertical axis wind turbine with a reactive shield system to increase efficiency by reducing drag on blades facing away from the wind. The shield changes shape based on wind direction to protect the opposite blade from wind pushback while allowing full exposure for the lead blade. This allows higher rotation speed and requires less wind to spin the turbine, increasing efficiency.

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Introduction Swept blades can achieve effective load reduction, thereby improving the operational performance of wind turbines. To investigate impact hundred-meter-level swept on characteristics turbines, this paper takes IEA-15 MW turbine as subject. Methods Based free-wake lifting line theory model and geometrically exact beam model, straight under rated conditions are compared. Results discussion The results show that undergo greater torsional deflection, reducing angle attack achieving reduction. influence different sweep parameters is also discussed. study finds reduction effects starting point index similar, while effect displacement most significant, it becomes more pronounced increases. Additionally, yaw conditions, increases, gradually increasing deflection decreasing amplitude flapwise speed fluctuation lead to a downward trend in both mean attack.

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This study explores a novel morphing blade design methodology to enhance the aerodynamic performance of NREL 1.5 MW wind turbine while addressing structural constraints. The proposed approach applies targeted leading and trailing edges sections, utilizing streamlined parameterization framework with four shape variables per airfoil: two deflection angles deformation starting points. process is modeled using an m-degree function optimized genetic algorithm maximize power generation minimizing displacement thrust forces. Turbine initially assessed Blade Element Momentum (BEM) theory validated through high-fidelity Computational Fluid Dynamics (CFD) simulations based on Reynolds-Averaged NavierStokes (RANS) equations k- turbulence model. Results demonstrate significant coefficient improvements up 23.8%, 10%, 7% at speeds 11.5 m/s, 8 4 respectively, compared baseline configuration. These findings highlight potential technologies improve energy efficiency in turbines adhering practical limitations.

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ABSTRACT Wind turbines operating in unsteady and complex environments often encounter asymmetric vortex flows on the suction side of blade, leading to airflow separation dynamic stall. These issues significantly impact aerodynamic performance energy efficiency wind turbines. Trailing edge flaps are an active flow control method mitigate stall; however, there is a lack research regarding regulatory relationship between airfoil parameters, trailing flap oscillation angles, parameters. To address this gap, numerical study employs multiblock overlapping grid technique customprogrammed simulate by coordinating motion main wing during pitching oscillations. Aerodynamic parameters airfoils were calculated investigate deflection direction, amplitude, other turbine blade section thrust, torque, characteristics under stall conditions. An optimized curve was produced. The results show that when occurred speed low, lift coefficient can be increased approximately 23% with amplitude amp1 = 40 same direction; moreover, tangential force torque value concurrently increased. Adjusting reduced ... Read More

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The blades of wind turbines constitute key components for converting energy into electrical energy, and modifications to blade airfoil geometry can effectively enhance aerodynamic performance turbine. trailing edge flap enables load control on the through adjustments its motion geometric parameters, thereby overcoming limitations inherent in conventional pitch systems. However, current research primarily emphasizes isolated parametric effects performance, with limited exploration interactions between multiple design variables. This study adopts a numerical simulation approach based FFA-W3-241 DTU 10 MW. Geometric deformations are achieved by manipulating influence is analyzed using computational fluid dynamics methods. Investigations conducted lengths deflection angles characteristics. results show existence an optimal length angle combination. Specifically, when 0.1c 10, lift-to-drag ratio demonstrates significant improvement under defined operational conditions. These findings offer practical guidance optimizing turbine designs.

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This paper investigate the flow separation behavior of a turbine blade using NACA 63-415 airfoil in three arrangements- without slot, with single double slot. Computational fluid dynamic simulation are used to study at 0 20 degree angle attack.to how begins and develops. The targets determination significant attack which initiates since it influences both efficiency performance blade. Important aerodynamics factors like pressure distribution, velocity contours impact turbulence assesses determine change patterns. Further research explores whether slot modification leading edge efficient controlling or postponing hence aerodynamic efficiently can be improved. Single existence is explored find their effectiveness enhancing lift drag ratio, lowering intensity ensuring smoother on surface.

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