Abstract Bio-inspired oscillatory foil propulsion has the ability to traverse various propulsive modes by dynamically changing the foil’s heave and pitch kinematics. This research characterizes the propulsion properties and wake dynamics of a symmetric oscillating foil, specifically targeting the high Reynolds number operation of small to medium surface vessels whose propulsive specifications have a broad range of loads and speeds. An unsteady Reynolds-averaged Navier–Stokes (URANS) solver with a k- ω SST turbulence model is used to sweep through pitch amplitude and frequency at two heave amplitudes of h 0 ∕ c = 1 and h 0 ∕ c = 2 at R e = 1 0 6 . At h 0 ∕ c = 2 , the maximum thrust coefficient is C T = 8 . 2 due to the large intercepted flow area of the foil, whereas at a decreased Strouhal number the thrust coefficient decreases and the maximum propulsive efficiency reaches 75%. Results illustrate the kinematics required to transition between the high-efficiency and high-thrust regimes at high Reynolds number and the resulting changes to the vortex wake structure. The unsteady vortex dynamics throughout the heave–pitch cycle strongly influence the characterization of thrust and propulsive efficiency, and are classified into flow regimes based on performance and vortex structure.

中文翻译：

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可变推力和高效率推进与高雷诺数的振荡箔

摘要 仿生振荡水翼推进能够通过动态改变水翼的升沉和俯仰运动学来穿越各种推进模式。这项研究表征了对称振荡箔的推进特性和尾流动力学，特别针对推进规格具有广泛负载和速度范围的中小型水面船舶的高雷诺数操作。具有 k-ω SST 湍流模型的非定常雷诺平均纳维-斯托克斯 (URANS) 求解器用于在 R e 处的 h 0 ∕ c = 1 和 h 0 ∕ c = 2 的两个垂荡幅度处扫描桨距幅度和频率= 1 0 6 。在 h 0 ∕ c = 2 时，最大推力系数为 CT = 8 。2 由于箔的截流面积大，而在降低 Strouhal 数时，推力系数降低，最大推进效率达到 75%。结果说明了在高雷诺数下在高效和高推力状态之间转换所需的运动学以及由此产生的涡流尾流结构变化。整个升沉-俯仰循环中的不稳定涡流动力学强烈影响推力和推进效率的表征，并根据性能和涡流结构分为流态。