Numerical study on hydrodynamic performance of an underwater propulsive wing propulsor

Lu, Jiaxin; Lu, Yang; Zhang, Ronghao; Wang, Junjie; Tang, Zhili

doi:10.1016/j.oceaneng.2023.115293

Cited by 3 publications

(1 citation statement)

References 26 publications

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“…Kumar et al [17] demonstrated that flapping fins, when moving in a compound harmonic motion, can generate thrust, and the propulsive performance is correlated with the frequency. Li et al [18] found an optimal pitch amplitude for flapping propulsion. Han et al [19] concluded that non-sinusoidal flapping motion exhibits superior energy harvesting performance.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study of the Effects of Asymmetric Pitching Motion on the Hydrodynamic Propulsion of a Flapping Fin

Wang,

Niu,

et al. 2024

Symmetry

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Aquatic organisms have evolved exceptional propulsion and even transoceanic migrating capabilities, surpassing artificial vessels significantly in maneuverability and efficiency. Understanding the hydrodynamic mechanisms of aquatic organisms is crucial for developing advanced biomimetic underwater propulsion vehicles. Underwater tetrapods such as sea turtles use fins or flippers for propulsion, which exhibit three rotational degrees of freedom, including flapping, sweeping, and pitching motions. Unlike previous studies that often simplify motion kinematics, this study employs a specially designed experimental device to mimic sea turtle fins’ motion and explore the impact of pitching amplitude, asymmetric pitching kinematics, and pausing time on lift and thrust generation. Force transducers and particle image velocimetry techniques are used to examine the hydrodynamic forces and flow field, respectively. It is found that boosting the fin’s pitching amplitude enhances both its lift and thrust efficiency to a certain extent, with a more pronounced effect on thrust performance. Surprisingly, the asymmetrical nature of the pitching angle’s pausing time within one flapping cycle significantly influences the lift and thrust characteristics during sea turtle swimming; extending the pausing time during the forward and upward flapping process improves lift efficiency; and prolonging the pausing time during the downward flapping process enhances thrust efficiency. Furthermore, the mechanism for high lift and thrust efficiency is revealed by examining the vortices shed from the fin during different motion kinematics. This research contributes to a more comprehensive understanding of the fin’s hydrodynamic characteristic, providing insights that can guide the design of more efficient biomimetic underwater propulsion systems.

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Section: Introductionmentioning

confidence: 99%

An Experimental Study of the Effects of Asymmetric Pitching Motion on the Hydrodynamic Propulsion of a Flapping Fin

Wang,

Niu,

et al. 2024

Symmetry

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Numerical study on the hydrodynamic performance and wake dynamics of propulsive wing propulsors with different cross-flow fans

Lu,

Wang

et al. 2024

Physics of Fluids

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The propulsive wing propulsor (PWP), which means an underwater thruster equipped with a wing, a cross-flow fan (CFF), and a deflector, is capable of generating both horizontal thrust and vertical lift, thus enhancing the maneuverability of underwater vehicles and serving as a propulsion device. The hydrodynamic performance of the PWP is significantly influenced by the blade number it possesses. An unsteady numerical method based on the Reynolds-averaged Navier–Stokes equations was developed to examine the impact mechanism of blade number on the hydrodynamic performance, load fluctuation, and wake evolution of the PWP. The results indicate that as the blade number increases, the hydrodynamic forces, power, and propulsive efficiency of the PWP gradually increase. When the blade number exceeds 26, the performance of the PWP tends to stabilize. Insufficient blades can lead to turbulence in the internal flow of the CFF, intensifying interference between blade vortices, resulting in secondary peaks and frequency-domain bifurcations in hydrodynamics. With an increasing blade number, disturbances to the blade vortices decrease, enhancing the periodicity of PWP hydrodynamic fluctuations, but there may be an increase in high-frequency noise levels. The wake modes of the PWP undergo four transitions: double vortex pair mode, single vortex pair mode, single vortex pair + single vortex mode, and vortex strip mode. Disturbed blade vortices promote the transition of vortex pair shedding modes in the PWP wake, thereby causing variations in the periodicity of PWP hydrodynamics. Excessive amplitude and frequency may lead to structural fatigue damage in the PWP.

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Comparison on Aerodynamic Characteristics of a Propulsive Wing and a Rotor in Hover

Lu,

Tang

2024

Proceedings of the 2024 3rd International Symposium on Intelligent Unmanned Systems and Artificial Intelligence

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Numerical study on hydrodynamic performance of an underwater propulsive wing propulsor

Cited by 3 publications

References 26 publications

An Experimental Study of the Effects of Asymmetric Pitching Motion on the Hydrodynamic Propulsion of a Flapping Fin

An Experimental Study of the Effects of Asymmetric Pitching Motion on the Hydrodynamic Propulsion of a Flapping Fin

Numerical study on the hydrodynamic performance and wake dynamics of propulsive wing propulsors with different cross-flow fans

Comparison on Aerodynamic Characteristics of a Propulsive Wing and a Rotor in Hover

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