Flow Control over the Blunt Trailing Edge of Wind Turbine Airfoils Using Circulation Control

Xu, He-Yong; Dong, Qing-Li; Qiao, Chen-Liang; Ye, Zhengyin

doi:10.3390/en11030619

Cited by 11 publications

(5 citation statements)

References 36 publications

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“…In particular, the lift enhancement was governed by increasing C µ and/or decreasing slot-height; nevertheless, the performance of the modified aerofoil was degraded in the absence of CC-actuation, (as compared to the reference aerofoil). Therefore, a partial-CC (PCC) flow-control design was proposed as an effective, efficient, and reliable flow control for blunt trailing-edge wind turbines [287], generating higher lift increments with slightly increased drag, at lesser Coanda-actuation power. However, unlike CC, PCC does not degrade performance in the absence of actuation.…”

Section: Circulation Controlmentioning

confidence: 99%

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

Akhter

Omar

2021

Energies

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It is projected that, in the following years, the wind‐energy industry will maintain its rapid growth over the last few decades. Such growth in the industry has been accompanied by the desirability and demand for larger wind turbines aimed at harnessing more power. However, the fact that massive turbine blades inherently experience increased fatigue and ultimate loads is no secret, which compromise their structural lifecycle. Accordingly, this demands higher overhaul‐and‐maintenance (O&M) costs, leading to higher cost of energy (COE). Introduction of flow‐control devices on the wind turbine is a plausible solution to this issue. Flow‐control mechanisms feature the ability to effectively enhance/suppress turbulence, advance/delay flow transition, and prevent/promote separation, leading to enhancement in aerodynamic and aeroacoustics performance, load alleviation and fluctuation suppression, and eventually wind turbine power augmentation. These flow‐control devices are operated primarily under two schemes: passive and active control. Development and optimization of flow‐control devices present the potential for reduction in the COE, which is a major challenge against traditional power sources. This review performs a comprehensive and up‐to‐date literature survey of selected flow‐control devices, from their time of development up to the present. It contains a discussion on the current prospects and challenges faced by these devices, along with a comparative analysis centered on their aerodynamic controllability. General considerations and conclusive remarks are presented after the discussion.

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Section: Circulation Controlmentioning

confidence: 99%

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

Akhter

Omar

2021

Energies

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“…According to the previous finding proposed by Xu,32,33 there are two control stages of CC, which are commonly referred to as the separation control stage and the super-CC stage, and the division of the CC control stage is determined by the jet separation location on the Coanda surface. When the separation location is close to the bottom end of the Coanda surface and will not move further along the surface with increasing C μ, jet , a typical CC airfoil with a round TE at a low subsonic freestream speed is considered in the super-CC stage.…”

Section: Division Of Circulation Control Stagesmentioning

confidence: 99%

“…No obvious forward movement of the separation location can be identified from the flow fields with a close-up for the Coanda surfaces illustrated in Figure 5(e) to (f). And hence, according to the definition of the two control stages proposed by Xu, 32,33 the ACTE is in the super-CC stage. When C μ, jet is less than 0.0018, the significant movement of the separation location with increasing C μ, jet can be found in Figure 5(b) to (d).…”

Section: Division Of Circulation Control Stagesmentioning

confidence: 99%

Computational evaluation of geometric effects on aerodynamic performance of circulation control airfoils

Chu

Qiao

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The geometric effects of Coanda trailing edges on the aerodynamic performance of an airfoil are numerically evaluated for a range of different freestream Mach numbers and momentum coefficients. A Circulation control (CC) airfoil with a circular trailing edge (ACTE) proves to have better control effectiveness at low subsonic freestream speeds (Mach = 0.1). A CC airfoil having an elliptic trailing edge (AETE) outperforms the ACTE at high subsonic flow conditions. The occurrence of C μ-stall for the AETE is greatly postponed, and meanwhile the maximum net lift coefficient increment achieved for the AETE (Δ C L = 0.51) is slightly higher than that of the ACTE (Δ C L = 0.50) at Mach 0.6. Compared to the ACTE, the AETE is found to have better control consistency at different operating velocities and better control stability when the Coanda jet is supersonic. Through careful consideration of the aerodynamic performance and the control effects, the most appropriate axial ratio for an AETE ellipse is within the interval from 1.5 to 2. Finally, the flow field instability phenomenon and the jet detachment induced by the supersonic Coanda jet are investigated. A self-sustained shock-wave instability phenomenon without jet detachment is first observed in this paper.

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“…The results show that the steady-suction perpendicular to the airfoil surface can effectively improve the aerodynamic performance of the airfoil [10]. AFC technology was widely used in wind turbine lift drag reduction [11,12], ground vehicle energy-saving drag reduction [13][14][15], aircraft airfoil aerodynamic performance improvement [16][17][18][19], and other fields. Overall, AFC technology has broad application prospects in many fields.…”

Section: Introductionmentioning

confidence: 96%

Analysis of the Steady-Stream Active Flow Control for the Blended-Winged-Body Underwater Glider

Liu

Song

2023

JMSE

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The BWB-UG is a glider with a smooth and integrated fuselage and wing. Its lift-to-drag properties are some of the most significant factors affecting its performance. In order to improve its hydrodynamic characteristics, the method of steady-stream active flow control (SS-AFC) is proposed. The computational fluid dynamics method is used to numerically investigate the SS-AFC of the BWB-UG. The mechanism of the SS-AFC effect on the lift-to-drag characteristics is revealed from the flow field aspect. The flow field of the BWB-UG before and after installing the SS-AFC was simulated using FLUENT. The results show that the SS-AFC can effectively optimise the hydrodynamic characteristics of the BWB-UG and can optimise the structure of the flow field around the BWB-UG. The steady-suction AFC can increase the lift-to-drag ratio of the BWB-UG by up to 45.01%. With the steady-jet AFC, the lift-to-drag ratio of the BWB-UG can be increased by as much as 93.17%.

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Flow Control over the Blunt Trailing Edge of Wind Turbine Airfoils Using Circulation Control

Cited by 11 publications

References 36 publications

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

Computational evaluation of geometric effects on aerodynamic performance of circulation control airfoils

Analysis of the Steady-Stream Active Flow Control for the Blended-Winged-Body Underwater Glider

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