Drag Reduction for Wind Turbine Blades

The uneven distribution of electricity demand across Indonesia necessitates the development Renewable Energy Sources, particularly wind energy. This study evaluates performance efficiency horizontal-axis turbines equipped with two blade types: taper and taperless, both using NACA 0012 airfoil. Aerodynamic simulations were conducted QBlade software. Wind speed data from 2017 to 2022 sourced European Centre for Medium-Range Weather Forecasts (ECMWF), while consumption obtained Statistics Bureau Pesisir Barat Regency. A quantitative approach descriptive graphical analysis was employed compare metrics designs. results show that taperless achieves higher power coefficient (Cp) torque (Ct) values compared blade, although produces greater (T). energy conversion reached 347.6 kWh, representing an increase approximately 4.83% over 331.6 kWh generated by blade. Further indicates 19 taperless-blade are required meet daily 6,545 in These findings support recommendation adopt blades improved utilization region.

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Wind turbine with improved blade connecting tension members to extract more power from the wind. The tension members have a core surrounded by a textured layer. The core provides strength and the textured layer has a rougher surface. This texture reduces drag compared to a smooth core. The rougher texture also erodes less compared to a smooth surface in high wind conditions. The textured layer can be applied over the core in layers with different roughnesses to optimize the balance between drag reduction and erosion resistance.

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Airfoils for rotating turbines and propellers that improve efficiency and reduce drag compared to conventional airfoils. The airfoils have curved helical shapes with fins attached to the blades. The fins are positioned asymmetrically on the upper and lower halves of the blades. This configuration allows the fluid to flow through channels between the fins. It provides better connectedness and reduces drag compared to straight blades. The fins also divide the helical sections into equal parts. This allows uniform spacing between fins on each blade.

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Abstract. Wind farm flow control has demonstrated significant potential to increase wind power and energy production. Two commonly used methods are wake steering, which entails yaw misaligning individual turbines deflect wakes laterally, induction control, typically modifies the thrust coefficients of reduce deficits. These two approaches often studied utilized independently. This study investigates combination both these strategies, termed joint yaw-induction control. By synergistically controlling turbine angles levels, increased can be achieved compared either or in isolation. research leverages Unified Momentum Model capitalize on interplay between misalignment coefficient a rotor velocities generated by turbine. The is integrated with blade element modeling yield momentum model that predicts forces arbitrary input yaw, pitch, tip speed ratio, also initial needed for far-wake models. Forward-mode automatic differentiation into efficiently optimize strategies using gradient-based optimization. Using fast-running model, coupling Gaussian we demonstrate outperforms leading increases... Read More

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Structured body to reduce pressure drag on objects while also minimizing friction drag on fluids. The structured body has a curved face that comes into contact with the fluid and includes a frictional portion spreading in the direction of curvature, adjacent to a smooth portion. The frictional portion has features like protrusions, disturbance structures, or flow rectifiers. The smooth portion has lower height and width compared to the frictional portion. This configuration reduces separation of the fluid from the curved surface while still allowing flow attachment.

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A flow control framework based on linear stability analysis is proposed, focusing reducing the aerodynamic drag due to dynamic stall through a finite-window temporal actuation. The methodology applied periodically plunging SD7003 airfoil. Finite-time Lyapunov exponent (FTLE) fields reveal saddle point near airfoil leading edge, where shear layer forms and feeds vortex (DSV). local conducted at this identifies KelvinHelmholtz instability, most unstable eigenvalue frequencies remain constant when variation in effective angle of attack minimal. findings from FTLE are used inform position finite duty cycle periodic blowing suction actuation wall-resolved large-eddy simulation (LES). present reduces by 77.5% during motion while maintaining same performance as continuous throughout entire cycle. LES results demonstrate that disturbances stability-analysis-informed modify leading-edge dynamics, preventing formation coherent DSV significantly drag.

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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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