Leading edge tubercle on wind turbine blade to mitigate problems of stall, hysteresis, and laminar separation bubble

Joseph, Jibin; Sathyabhama, A.

doi:10.1016/j.enconman.2022.115337

Cited by 17 publications

(4 citation statements)

References 29 publications

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“…Miklosovic et al [18], conducted experimental trials on sinusoidal leading-edge wings, and their findings revealed that wings with larger amplitudes exhibited a more gradual stall pattern, attributed to stalls occurring later in the regions behind the peaks compared to those behind the troughs. Other scholars validated this through an experimental and numerical investigation of a rectangular wing incorporating the Wavy Leading Edge effect, demonstrating improved lift force during pitching motion with minimized stall [19][20][21], suggesting potential applications in wind turbines [22][23][24]. The experimental investigation performed by N. Karthikeyan et al [25,26] examined the impact of wavy leading edges, revealing tubercles' effectiveness in maintaining attached flow and reducing recirculating zones, although their influence on separation point variability and wake width post-stall requires further exploration.…”

Section: Introduction 1backgroundmentioning

confidence: 87%

Investigating Mechanical Response and Structural Integrity of Tubercle Leading Edge under Static Loads

Esmaeili,

Jabbari,

Zehtabzadeh

et al. 2024

Modelling

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This investigation into the aerodynamic efficiency and structural integrity of tubercle leading edges, inspired by the agile maneuverability of humpback whales, employs a multifaceted experimental and computational approach. By utilizing static load extensometer testing complemented by computational simulations, this study quantitatively assesses the impacts of unique wing geometries on aerodynamic forces and structural behavior. The experimental setup, involving a Wheatstone full-bridge circuit, measures the strain responses of tubercle-configured leading edges under static loads. These measured strains are converted into stress values through Hooke’s law, revealing a consistent linear relationship between the applied loads and induced strains, thereby validating the structural robustness. The experimental results indicate a linear strain increase with load application, demonstrating strain values ranging from 65 με under a load of 584 g to 249 με under a load of 2122 g. These findings confirm the structural integrity of the designs across varying load conditions. Discrepancies noted between the experimental data and simulation outputs, however, underscore the effects of 3D printing imperfections on the structural analysis. Despite these manufacturing challenges, the results endorse the tubercle leading edges’ capacity to enhance aerodynamic performance and structural resilience. This study enriches the understanding of bio-inspired aerodynamic designs and supports their potential in practical fluid mechanics applications, suggesting directions for future research on manufacturing optimizations.

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Section: Introduction 1backgroundmentioning

confidence: 87%

Investigating Mechanical Response and Structural Integrity of Tubercle Leading Edge under Static Loads

Esmaeili,

Jabbari,

Zehtabzadeh

et al. 2024

Modelling

View full text Add to dashboard Cite

show abstract

“…Shi et al [6] tested the bionic turbine with LE tubercles in the cavitation channel, measured cavitation parameters and noise performance under various operating settings, and compared it to a reference turbine. Joseph and Sathyabhama [7] found that the airfoil with tubercles has a multi-step soft stall characteristic, which is different from the single-step deep stall characteristic of the airfoil without tubercles.…”

Section: Introductionmentioning

confidence: 97%

“…Several studies on the flow pattern of airfoils with leading-edge (LE) convex structures have mostly focused on the flow separation mechanism [1][2][3]. Wei et al [4] carried out a visual investigation of the airfoil with the LE tubercle in the water tunnel.…”

Section: Introductionmentioning

confidence: 99%

Investigation of dynamic characteristics of hydrofoil with leading-edge tubercles

Fan,

Sun,

et al. 2024

J. Phys.: Conf. Ser.

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The convex structure of a humpback whale flipper is included in the airfoil design to investigate the control principle of the dynamic stall process. The effect of two different types of tubercles on the dynamic stall process of airfoils was investigated. The distribution of dynamic hysteresis loops and pressure fields with streamlines was used to explain the properties of the dynamic flow field and the emergence of dynamic stall vortices. The results demonstrate that the airfoils with tubercles have stronger hysteretic characteristics in the pre-stall region, and the ζ CM of mod-1 is increased by 51.33%, indicating stronger torsional hydroelastic stability. In the post-stall region, mod-2 is always in a condition of significant flow separation, which impairs the torsional hydrodynamic stability of the airfoil and has the potential to cause flutter. These findings suggest that leading-edge tubercles offer a negligible advantage in reducing airfoil dynamic stall, and their significance warrants further investigation.

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“…Moreover, over the last few years numerous studies has been carried out to control flow in the subsonic [3][4][5][6][7][8][9][10][11][12][13] and the transonic flow regimes [14][15][16][17]. The deployment of tubercle in various rotating fluid machinery application such as propeller [18,19], wind turbines [18,[20][21][22][23][24][25][26][27][28][29][30] and on the tidal turbine [31][32][33] to improve their aerodynamic performance, by controlling dynamic stall is gaining research attention over last decade. In addition to this, flow separation is the major problem, which degrades aircraft wing aerodynamic performance at higher angle of attack.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Performance Enhancement of Low Aspect Ratio Military Drone Aircraft Wing through Employing Leading Edge Tubercles

2024

IJFMR

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Present study aim to improve the aerodynamic performance of low Aspect Ratio (AR) military drone aircraft wing, through employing leading edge tubercle. For that purpose two wing model were design one with smooth leading edge and second with tubercle leading edge. The wing models were developed by using NACA0012 airfoil profile, whereas tubercles of amplitude 5% of chord (c) and wavelength of 11% of c is employed. The numerical simulation as performed at chord based Reynolds number of 140000 in pre-stall and post stall regime. The computational fluid dynamic simulation is performed at different angle of attack ranging from 0 degree to 25 degree with the interval of 5 degree. Computational Fluid Dynamics (CFD) results reveal that tubercle at the leading edge of the low AR wing has favorable effect on the wing performance. Aerodynamic performance of both smooth leading edge and tubercle leading edge wing is similar up to 15o angle of attack, whereas at 20 degree and 25 degree significant improvement in Lift-to-Drag L/D ratio is observed. It is estimated that at maximum increment of 53% in lift coefficient ii achieved at 25 degree angle of attack for as compared to smooth LE wing model. Moreover, maximum 20.5% decrease in drag coefficient is estimated in case of tubercle leading edge as compared to baseline model at 20 degree angle of attack. The critical observation of field around the tubercle leading edge wing is found that tubercles restrict flow separation through generation of low strength vortices; these vortices enhance momentum exchange within the boundary layer.

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Leading edge tubercle on wind turbine blade to mitigate problems of stall, hysteresis, and laminar separation bubble

Cited by 17 publications

References 29 publications

Investigating Mechanical Response and Structural Integrity of Tubercle Leading Edge under Static Loads

Investigating Mechanical Response and Structural Integrity of Tubercle Leading Edge under Static Loads

Investigation of dynamic characteristics of hydrofoil with leading-edge tubercles

Aerodynamic Performance Enhancement of Low Aspect Ratio Military Drone Aircraft Wing through Employing Leading Edge Tubercles

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