Gust–Airfoil Coupling with a Loaded Airfoil

Young, Anna; Smyth, Amanda

doi:10.2514/1.j059688

Cited by 5 publications

(5 citation statements)

References 11 publications

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“…The modified theories are obtained by replacing the quasi-steady term in the original formula with the static lift coefficient measured under steady conditions. Under vertical-gust conditions, when α is smaller than the stall angle of attack, the amplitude of the lift coefficient decreases with α , which is similar to the result obtained by Young & Smyth (2021). After α reaches the stall angle of attack, the amplitude of the lift coefficient increases significantly.…”

Section: Experimental Validation Of Theoriessupporting

confidence: 88%

“…It should be noted that k 2 is of the same order of magnitude as k 1 in the research of Young & Smyth (2021), whereas k 2 is far less than k 1 in this research. However, experimental results are similar in that the lift coefficient amplitude decreases with α for small angles of attack.…”

Section: Lift Coefficient Amplitudementioning

confidence: 43%

“…In addition, their results confirmed the validity of both theories for a NACA0006 airfoil with a zero angle of attack. Young & Smyth (2021) selected an airfoil with a thickness of 21 % chord and camber of 2 % chord for testing. The results suggested that the Atassi function can predict the unsteady lift experienced by airfoils for vertical gusts with a longitudinal oscillating component under small gust amplitude.…”

Section: Introductionmentioning

confidence: 99%

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Airfoil response to periodic vertical and longitudinal gusts

Wang,

Feng,

Cao

et al. 2024

J. Fluid Mech.

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Gust response has consistently been a concern in engineering. Critical theories have been proposed in the past to predict the unsteady lift response of an airfoil experiencing vertical gusts by Atassi, and longitudinal gusts by Greenberg. However, their applicability for an airfoil with non-zero angles of attack still needs clarification. Thus, force measurements are conducted to examine these theories’ validity and quasi-steady corrections are applied to compensate potential disparities between the idealised and real flow conditions. Velocity measurements are performed to scrutinise the effect of gusts on the flow around the airfoil, and subsequently to reveal the underlying mechanism governing the airfoil's response to gust-induced perturbations. In the study, two pitching vanes are arranged upstream to generate periodic vertical and longitudinal gusts, whereas a downstream airfoil with angles of attack of 0–12° is subjected to two gust types. It is found that Greenberg's theory demonstrates superior predictive capability in pre-stall regimes, with the potential for its effectiveness to be expanded to post-stall regimes through theoretical refinements. In contrast, Atassi's theory exhibits significant deviations from experimental outcomes across the measured angles of attack. Nevertheless, a modified version of the theory aligns better with experimental results at small angles of attack, whereas substantial discrepancies persist as the angle of attack increases. In the pre-stall regime, the aerodynamic response of the airfoil to vertical gusts displays a linear correlation with the flow angle near the leading edge. In the post-stall regime, the vertical gust induces dynamic stall of the airfoil. The flow angle has an essential effect on the lift coefficient but it alone is inadequate to dictate the trend of the lift coefficient. The vorticity statistics show that negative vortex circulation strongly correlates with the lift coefficient. Thus, further correction of the theory or a new vortex model can be expected to predict the lift variation.

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Section: Experimental Validation Of Theoriessupporting

confidence: 88%

Section: Lift Coefficient Amplitudementioning

confidence: 43%

Section: Introductionmentioning

confidence: 99%

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Airfoil response to periodic vertical and longitudinal gusts

Wang,

Feng,

Cao

et al. 2024

J. Fluid Mech.

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“…Lastly, it is expected that encounters between gusts and floating VAWTs will alter the performance and dynamics of the turbine. Recent advances in gust and aerofoil encounters [96,97] hint that gust loading on the blade could decrease its fatigue life. However, it remains unknown what the gust influence is in the aerodynamics and system dynamics of a floating VAWT.…”

Section: Way Forward To Increase Trlmentioning

confidence: 99%

Floating Offshore Vertical Axis Wind Turbines: Opportunities, Challenges and Way Forward

Arredondo-Galeana

2021

Energies

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The offshore wind sector is expanding to deep water locations through floating platforms. This poses challenges to horizontal axis wind turbines (HAWTs) due to the ever growing size of blades and floating support structures. As such, maintaining the structural integrity and reducing the levelised cost of energy (LCoE) of floating HAWTs seems increasingly difficult. An alternative to these challenges could be found in floating offshore vertical axis wind turbines (VAWTs). It is known that VAWTs have certain advantages over HAWTs, and in fact, some small-scale developers have successfully commercialised their onshore prototypes. In contrast, it remains unknown whether VAWTs can offer an advantage for deep water floating offshore wind farms. Therefore, here we present a multi-criteria review of different aspects of VAWTs to address this question. It is found that wind farm power density and reliability could be decisive factors to make VAWTs a feasible alternative for deep water floating arrays. Finally, we propose a way forward based on the findings of this review.

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“…Following the procedure laid out by Young and Smyth [18], the measured lift coefficient amplitude is computed with…”

Section: Force Modellingmentioning

confidence: 99%