发表机构
Technion – Israel Institute of Technology（以色列理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过Roshko标度发现，昆虫悬停中前缘涡的形成遵循约0.15至0.17的通用斯特劳哈尔数范围，统一了经典分离流与昆虫飞行的涡旋动力学。
AI 中文摘要
扑动昆虫翅膀产生前缘涡（LEVs），这些涡旋提供了悬停所需的大部分升力，然而控制其形成的频率尚未与经典涡旋脱落联系起来。针对钝体尾流的Roshko标度，结合Sigurdson对壁面受限分离流的扩展，确定了一个通用的涡旋形成斯特劳哈尔数范围，约为0.15至0.17。在此，我们表明这一相同范围同时控制着固定翼和悬停昆虫翅膀上的前缘涡形成。我们首先为固定平板翼发展了一个近似标度，其中离散的前缘涡由周期性前缘扰动产生，并表明最大升力始终出现在这一通用斯特劳哈尔数范围内。在悬停昆虫中，每个平移半冲程形成一个前缘涡，使得相同的框架能够应用于已发表的飞行数据。尽管形态、运动学和雷诺数存在巨大差异，昆虫数据仍恢复出相同的斯特劳哈尔数范围。这些结果揭示了一个共同的涡旋形成时间尺度，将经典分离流、人工生成的前缘涡以及维持昆虫悬停的自然前缘涡联系起来。
英文摘要
Flapping insect wings generate leading-edge vortices (LEVs) that produce much of the lift required for hovering, yet the frequency governing their formation has not been connected to classical vortex shedding. Roshko scaling for bluff-body wakes, together with the Sigurdson extension to wall-bounded separated flows, identifies a universal vortex-formation Strouhal-number range of approximately 0.15 to 0.17. Here we show that this same range governs LEV formation on both stationary wings and hovering insect wings. We first develop an approximate scaling for stationary flat-plate wings in which discrete LEVs are generated by periodic leading-edge perturbations, and show that maximum lift consistently occurs within the universal Strouhal range. In hovering insects, one LEV forms during each translational half-stroke, allowing the same framework to be applied to published flight data. Despite large differences in morphology, kinematics and Reynolds number, the insect data recover the same Strouhal range. These results reveal a common vortex-formation timescale linking classical separated flows, artificially generated LEVs and the natural LEVs that sustain insect hovering.
Comments4 figures; Supplementary Information included
