Investigation of hysteresis effect of cavitating flow over a pitching Clark-Y hydrofoil

Zhang, Mengjie; Feng, Fan; Wang, Meijing; Guo, Zhi-pu; Kang, Zhong; Huang, Biao

doi:10.1007/s10409-022-09031-x

Cited by 7 publications

(4 citation statements)

References 36 publications

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“…The cavitation number and static pressure of the current experiments are summarized in table 2. Cavitation disappears at σ = 11.9 due to the hysteresis phenomenon (Amini et al 2019;Zhang et al 2022). Good repeatability of the cavitation pattern was achieved for the specified cavitation numbers.…”

Section: Cavitation Modesmentioning

confidence: 80%

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Dynamics of cavitating tip vortex

Wang

Shao

2023

J. Fluid Mech.

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The three-dimensional dynamic behaviour of a tip vortex generated by a NACA $66_2$ -415 hydrofoil is investigated under wetted flow and cavitating conditions using time-resolved tomographic particle image velocimetry. Two main cavitation modes are studied, namely the breathing and double-helical modes. The time-averaged flow field consists of a system of two streamwise vortices for all three conditions. The shape of the tip vortex resembles that of the cavitation mode, instead of a circular cylinder. Multi-scale vortical structures are captured in the instantaneous flow field. The surface oscillation of the cavity contributes to the growth of Kelvin–Helmholtz instability over the tip vortex, leading to the onset of hairpin vortices. Stronger spanwise interaction between the tip vortex and flow separation of the hydrofoil is produced by cavitation, further intensifying the perturbation growth. The proper orthogonal decomposition analysis gives insight into the relationship between cavity oscillation and vortex instability. Two major types of unstable modes of the tip vortex are obtained, leading to serpentine centreline displacement and elliptical deformation motion. The selection of the dominant unstable mode is associated with cavity surface oscillation. For the wetted flow condition, the displacement mode dominates the growth of vortex perturbation, while for breathing mode cavitation, the most energetic unstable mode changes into an elliptical deformation pattern, the disturbance energy of which is negligible in the wetted flow condition. Consistency is found between the peak frequency of the deformation mode and the cavity resonance frequency, indicating the contribution of cavity oscillation to the disturbance growth and breakdown of the tip vortex.

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Section: Cavitation Modesmentioning

confidence: 80%

“…2019; Zhang et al. 2022). Good repeatability of the cavitation pattern was achieved for the specified cavitation numbers.…”

Section: Cavitation Modesmentioning

confidence: 99%

Dynamics of cavitating tip vortex

Wang

Shao

2023

J. Fluid Mech.

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“…The evolution of leading-edge vortex (LEV) and trailing-edge vortex (TEV) is the source of the unique aerodynamic characteristics of flapping wings (McCroskey 1982;Ellington et al 1996;Corke & Thomas 2015;Xiang et al 2021). To simplify the complex motion in practice, two-dimensional pitching and plunging motion is usually adopted in flapping wing research (Zhang et al 2022). In earlier studies, Theodorsen (1935) analytically derived a lift formula under assumptions of no leading-edge separation and continuous wake.…”

Section: Introductionmentioning

confidence: 99%

“…To simplify the complex motion in practice, two-dimensional pitching and plunging motion is usually adopted in flapping wing research (Zhang et al. 2022). In earlier studies, Theodorsen (1935) analytically derived a lift formula under assumptions of no leading-edge separation and continuous wake.…”

Section: Introductionmentioning

confidence: 99%

Lift generation mechanism of the leading-edge vortex for an unsteady plate

Li,

Feng,

Wang

et al. 2023

J. Fluid Mech.

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The lift generation mechanism of leading-edge vortex (LEV) in the case of a pitching and plunging plate is studied using an experimental approach and the improved discrete vortex method in this research. A formation condition of the secondary structure is introduced into the traditional discrete vortex method to compensate for the shortcomings in the simulation of the viscous effect between LEV and plate. The simulation of the secondary structure helps the improved method perform better in flow-field reconstruction and lift prediction. Accordingly, the lift generation mechanism of the LEV and influence of the secondary structure are studied. The lift contribution of the vortex structure is isolated and linearly decomposed into two parts according to sources of flow field: the quasi-potential flow part and the vortex-induced flow part. The vortex lift is defined as the lift contribution of the vortex structure in vortex-induced flow, which gives a new insight into the production of lift of the LEV. The lift generation mechanism through the discrete vortex method is verified and extended in viscous flow through experimental measurement. In addition, a vortex lift indicator based on the reverse flow of the LEV is proposed to examine the change of vortex lift in experimental measurement. The flow mechanism for the decline of vortex lift for different maximum effective angles of attack is revealed based on the vortex lift indicator. Furthermore, for the LEV-dominating flow, the indicator can also be applied in estimating the maximum value and corresponding critical time of overall lift in experiments.

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Vortex-induced energy loss of a mixed-flow waterjet pump under different operating conditions

Kan

et al. 2023

Acta Mech. Sin.

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Investigation of hysteresis effect of cavitating flow over a pitching Clark-Y hydrofoil

Cited by 7 publications

References 36 publications

Dynamics of cavitating tip vortex

Dynamics of cavitating tip vortex

Lift generation mechanism of the leading-edge vortex for an unsteady plate

Vortex-induced energy loss of a mixed-flow waterjet pump under different operating conditions

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