Numerical study of Wavy Blade Section for Wind Turbines

Kobæk, C. M.; Hansen, Martin Otto Lavér

doi:10.1088/1742-6596/753/2/022039

Cited by 10 publications

(6 citation statements)

References 9 publications

(12 reference statements)

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“…An experimental study was conducted by Miklosovic et al [2]. The blade model was NACA002 aerofoils to simulate a flipper and the Reynolds number was around 5×10 5 . A delayed separation and increasing lift was found.…”

Section: Introductionmentioning

confidence: 99%

“…The study declared that there was an enhancement in performances for the bumped wing with increasing in lift to drag ratio up to 17.6%. The leading-edge serration technique was used by Hansen et al [4] and Kobaek, [5]. It was observed that the lift coefficient enhanced in the post-stall regime.…”

Section: Introductionmentioning

confidence: 99%

“…Z. Čarija et al [8] studied a sinusoidal shape leading edge of the NACA0012 then compared it with a normal one utilised a Reynolds number of 1.8×10 5 . The wavy blade showed up to 50% higher lift to drag ratio over a range AOA than the normal blade.…”

Section: Introductionmentioning

confidence: 99%

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The aerodynamics of the wavy blade under the effect of fluctuated wind flow

Al-Bakri¹,

Aljuhashy²

2021

FME Transactions

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In the present study, the influence of the wavy edge blade on aerodynamic characteristics for the flow of blades at Reynolds number (Re) of 8×105 is numerically investigated based on the unsteady wind flow. Aerodynamic characteristics of a (sinusoidal leading edge) wavy NACA0015 aerofoil blade are carried out using ICEM 19.1 and ANSYS fluent. The numerical simulation is conducted then validated by experimental data with steady wind flow. This is conducted by employing the same Reynold's number in the experimental work. While, the unsteady flow was numerically performed at 1 Hz frequency of wind flow conditions. The main findings from this work show that the wavy blade can behave better in turbulent wind conditions with the maximum lift coefficient of 0.73 compared to 0.621 for the normal blade. However, the findings declare that the wavy blade stalled earlier than the normal one in the unsteady flow case. Similarly, it stalled at 12° angle of attack earlier than the normal one which was stalled at 14° in the steady flow case.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The aerodynamics of the wavy blade under the effect of fluctuated wind flow

Al-Bakri¹,

Aljuhashy²

2021

FME Transactions

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“…This is because of the generation of vortex pair from the peak (Tong et al , 2018; Rostamzadeh et al , 2013). The wavy design increases the aerodynamic efficiency (lift increases and drag decreases) at high angles (Kobæk and Hansen, 2016; Colpitts et al , 2020). The addition of wave shape increases the surface area of the wing and increases the friction drag at low angles.…”

Section: Introductionmentioning

confidence: 99%

Flow separation control using a bio-inspired nose for NACA 4 and 6 series airfoils

Mohamed

Yadav

Güven

2021

AEAT

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Purpose This paper aims to achieve an optimum flow separation control over the airfoil using a passive flow control method by introducing a bio-inspired nose near the leading edge of the National Advisory Committee for Aeronautics (NACA) 4 and 6 series airfoil. In addition, to find the optimised leading edge nose design for NACA 4 and 6 series airfoils for flow separation control. Design/methodology/approach Different bio-inspired noses that are inspired by the cetacean species have been analysed for different NACA 4 and 6 series airfoils. Bio-inspired nose with different nose length, nose depth and nose circle diameter have been analysed on airfoils with different thicknesses, camber and camber locations to understand the aerodynamic flow properties such as vortex formation, flow separation, aerodynamic efficiency and moment. Findings The porpoise nose design that has a leading edge with depth = 2.25% of chord, length = 0.75% of chord and nose diameter = 2% of chord, delays the flow separation and improves the aerodynamic efficiency. Average increments of 5.5% to 6° in the lift values and decrements in parasitic drag (without affecting the pitching moment) for all the NACA 4 and 6 series airfoils were observed irrespective of airfoil geometry such as different thicknesses, camber and camber location. Research limitations/implications The two-dimensional computational analysis is done for different NACA 4 and 6 series airfoils at low subsonic speed. Practical implications This design improves aerodynamic performance and increases the structural strength of the aircraft wing compared to other conventional high lift devices and flow control devices. This universal leading edge flow control device can be adapted to aircraft wings incorporated with any NACA 4 and 6 series airfoil. Social implications The results would be of significant interest in the fields of aircraft design and wind turbine design, lowering the cost of energy and air travel for social benefits. Originality/value Different bio-inspired nose designs that are inspired by the cetacean species have been analysed for NACA 4 and 6 series airfoils and universal optimum nose design (porpoise airfoil) is found for NACA 4 and 6 series airfoils.

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“…Inspired by the tubercles on the humpback whale flippers, leading-edge tubercles have been developed and utilized in airfoils and wings (e.g., [1][2][3][4][5][6][7][8][9]), hydrofoils (e.g., [10]), turbine blades (e.g., [11][12][13][14]) and propellers (e.g., [15]) in order to improve their aerodynamic and hydrodynamic performance, especially in terms of stall performances. Different shapes of the tubercles, including sinusoidal, semi-circular and wavy, with different amounts and heights of the tubercles have been attempted.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Turbine Blades with Leading-Edge Tubercles in Uniform Current

Shu-ling

Liu

Han

et al. 2021

Water

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Inspired by the tubercles on humpback whale flippers, leading-edge tubercles have been incorporated into the design of wings and turbine blades in an attempt to improve their hydrodynamic performance. Although promising improvements, especially in terms of the stall performance, have been demonstrated in the limited research that exists to date, the effectiveness of the leading-edge tubercles seems to be influenced by the base blade. This paper focuses on the introduction of sinusoidal leading-edge tubercles to a base blade developed from the classic NACA0018 airfoil, and numerically investigates the effectiveness of leading-edge tubercles on the hydrodynamics associated with the blade in uniform current with different attack angles. Both the macroscopic parameters, such as the lift and drag forces, and the micro-scale flow characteristics, including the vortex and flow separation, are analyzed. The results indicate that the leading-edge tubercles brings a significant influence on the hydrodynamic forces acting on the blade when subjected to an attack angle greater than 15°. This study also reveals the important role of the turbulence and flow separation on hydrodynamic loading on the blade and the considerable influence of the tubercles on such micro-scale flow characteristics. Although the conditions applied in this work are relatively ideal (e.g., the blade is fixed in a uniform flow and the end effect is ignored), the satisfactory agreement between the numerical and corresponding experimental data implies that the results are acceptable. This work builds a good reference for our future work on the hydrodynamic performance of tidal turbines which adopt this kind of blade for operating in both uniform and shearing currents.

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Numerical study of Wavy Blade Section for Wind Turbines

Cited by 10 publications

References 9 publications

The aerodynamics of the wavy blade under the effect of fluctuated wind flow

The aerodynamics of the wavy blade under the effect of fluctuated wind flow

Flow separation control using a bio-inspired nose for NACA 4 and 6 series airfoils

Numerical Investigation of Turbine Blades with Leading-Edge Tubercles in Uniform Current

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