Experimental investigation on the unsteady lift of an airfoil in a sinusoidal streamwise gust

Yang, Yang; Li, Mingshui; Ma, Cunming; Li, Shaopeng

doi:10.1063/1.4984243

Cited by 63 publications

(12 citation statements)

References 15 publications

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“…In this study, the unsteady lift on an oscillating airfoil encountering a sinusoidal streamwise gust is investigated using a multiple-fan actively controlled wind tunnel. The quality of the generated fluctuating flow was proved to be excellent (Yang et al 2017). The surface pressures of the airfoil are measured using DMS-4000 pressure scanners, and thus the lift force can be obtained by integration along the chord length of the airfoil.…”

Section: Introductionmentioning

confidence: 99%

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The unsteady lift of an oscillating airfoil encountering a sinusoidal streamwise gust

Yang

et al. 2020

J. Fluid Mech.

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Section: Introductionmentioning

confidence: 99%

“…The quality of the generated fluctuating flow was proved to be excellent (Yang et al. 2017). The surface pressures of the airfoil are measured using DMS-4000 pressure scanners, and thus the lift force can be obtained by integration along the chord length of the airfoil.…”

Section: Introductionmentioning

confidence: 99%

The unsteady lift of an oscillating airfoil encountering a sinusoidal streamwise gust

Yang

et al. 2020

J. Fluid Mech.

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“…Ma et al (2013) determined the 2D AAF of the bridge deck in a wind tunnel, the multiple actively-controlled fans were used to simulate the streamwise velocity fluctuations, while the vibrating wings were used to produce the vertical velocity fluctuations. Later, Yang et al (2017) studied the 2D AAFs of a thin airfoil in experimentally generated sinusoidal flow with discrete frequency. Recently, with the help of active generation wind tunnels, an effective method is obtained to generate the downstream flow field (Wu et al, 2021).…”

Section: Article History Abstractmentioning

confidence: 99%

Investigation of the 2D Aerodynamic Admittances of a Closed-Box Girder in Sinusoidal Flow Field

Zhang

et al. 2021

KSCE J Civ Eng

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This study investigates the aerodynamic admittances of a closed-box girder in both streamwise (u-) and vertical (w-) sinusoidal flow fields. A series of sinusoidal flows with discrete oscillation frequencies (f u = 0.2 − 1.2 Hz) and different oscillation amplitudes (Δu = 0.5 − 2.0 m/s) are experimentally generated, which are fully coherent in the span-wise direction. Meanwhile, the Computational Fluid Dynamics (CFD) method is utilized to simulate streamwise sinusoidal flows with higher frequencies (f u = 0.2 − 14 Hz). The u-turbulence-related two-dimensional aerodynamic admittance functions (2D AAFs) of the closed-box girder are identified frequency by frequency. On the other hand, the vertical sinusoidal flows are numerically simulated (f w = 0.2 − 14 Hz, Δw = 1.2 m/s), and the w-turbulence-related 2D AAFs are identified. Finally, the differences between u-, w-admittances and the equivalent ones are compared. The results indicate that u-and w-turbulence-related AAFs have different trends with the reduced frequency, and thus it is inaccurate to treat the contributions of u-and w-turbulence to admittances as equivalent in previous studies. Aerodynamic admittanceWind tunnel CFD Sinusoidal flows Closed-box girder CORRESPONDENCE Bo Wu

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“…However, Yang et al. (2017) found considerable discrepancies between experimental results and Greenberg's prediction even under attached flow conditions. It should be noted that they experimentally chose a dimensionless gust amplitude of σ = 0.2, which is larger than that selected by Granlund et al.…”

Section: Introductionmentioning

confidence: 97%

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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Experimental investigation on the unsteady lift of an airfoil in a sinusoidal streamwise gust

Cited by 63 publications

References 15 publications

The unsteady lift of an oscillating airfoil encountering a sinusoidal streamwise gust

The unsteady lift of an oscillating airfoil encountering a sinusoidal streamwise gust

Investigation of the 2D Aerodynamic Admittances of a Closed-Box Girder in Sinusoidal Flow Field

Airfoil response to periodic vertical and longitudinal gusts

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