AI 中文总结
本研究探究弦向柔性分布对波浪辅助拍动翼性能的影响，通过实验揭示全柔性构型提升推进效率、中柔性构型提升推力的规律，为波浪驱动无人水面航行器设计提供物理指导。
AI 中文摘要
本研究探究了推进器沿弦向的柔性空间分布对波浪辅助拍动翼的推力产生及推进效率的影响。已知柔性可提升推进性能，但其弦向布置的作用却鲜为人知。本研究通过沿尾翼移动挠曲位置来系统改变有效柔性长度，同时保持挠曲刚度和总弦长恒定。实验在静止流场中开展，升沉频率为0.8 Hz和1.25 Hz，无量纲升沉振幅h*为0.13和0.22。同时测量水动力、流场及尾翼运动学，以量化性能并阐明潜在的流固及流体相互作用。全柔性构型在所有工况下均实现更高的推进效率（最高约164%），这归因于射流持续性增强和流向涡间距增大，表明形成了更连贯、持续的动量射流。相比之下，中柔性构型在最大升沉频率和振幅下产生显著更高的推力（最高约66%），这由近尾流射流速度和动量通量的显著增加驱动。这些结果表明，柔性的弦向分布通过调节尾流连贯性和动量转移，决定了推力与推进效率之间的权衡关系。研究结果确立了柔性布置为拍动推进的关键设计参数，并为提升波浪驱动无人水面航行器的性能和续航提供了基于物理的指导。
英文摘要
This study investigates the influence of the spatial distribution of flexibility along a propulsor on thrust generation and propulsive efficiency in wave-assisted flapping foils. While flexibility is known to enhance propulsive performance, the role of its chordwise placement remains poorly understood. Here, the effective flexible length is systematically varied by shifting the flexure location along the tail while maintaining constant flexural rigidity and total chord length. Experiments are conducted in quiescent flow at heave frequencies of 0.8 Hz and 1.25 Hz, and non-dimensional heave amplitudes of h* = 0.13 and 0.22. Simultaneous measurements of hydrodynamic forces, flow fields, and tail kinematics are used to quantify performance and elucidate the underlying fluid-structure and fluid-particle interactions. The fully flexible configuration consistently achieves higher propulsive efficiency (up to approximately 164%) across all conditions, which is attributed to enhanced jet persistence and increased streamwise vortex spacing, indicative of a more coherent and sustained momentum jet. In contrast, the mid-flexible configuration yields substantially higher thrust (up to approximately 66%) at the largest heave frequency and amplitude, driven by a pronounced increase in near-wake jet velocity and momentum flux. These results demonstrate that the chordwise distribution of flexibility governs the trade-off between thrust and propulsive efficiency by modulating wake coherence and momentum transfer. The findings establish flexibility placement as a key design parameter in flapping propulsion and provide physics-based guidelines for enhancing the performance and endurance of wave-driven unmanned surface vehicles.
