This paper employs numerical simulation to study the hydrodynamics of porpoising behavior in dolphins. The virtual swimmer is a three-dimensional dolphin-like body with prescribed kinematics. A four-stage model of this behavior is proposed, including underwater acceleration, upward leap, air glide and downward dive. When the dolphin goes through these four stages, the time history of its displacement, velocity, force and energy could be solved to elucidate the rules. By varying oscillating frequency f and escape angle α, various behaviors of the swimmer are simulated to obtain their porpoising performance, which are evaluated by maximum leap height H_max, maximum leap distance D_max and leap efficiency η. The results show that both H_max and D_max are increasing functions of f, but their trend with α is not monotonic. For peak H_max generation, α occurs at 90°, while for peak D_max, α is ranging from 45° to 60° and nears 50°. As for efficiency, η increases slowly with the increase of α, and first increases and then decreases with the increase of f at a critical value between 7 Hz and 8 Hz. The findings may provide an important hydrodynamics basis for the biomimetic vehicle designs that mimic the porpoising motion of dolphins.

本文利用数值模拟研究了海豚在海豚中的行为。虚拟游泳者是具有规定运动学的三维海豚状身体。提出了这种行为的四阶段模型，包括水下加速，向上跳跃，滑翔和向下俯冲。当海豚经过这四个阶段时，可以解决其位移，速度，力和能量的时间历程，以阐明规则。通过改变振荡频率f和逃逸角α，可以模拟游泳者的各种行为，从而获得最佳的跳水性能，并通过最大跳跃高度H _max，最大跳跃距离D _max和跳跃效率进行评估η。结果表明，H _max和D _max都是f的递增函数，但它们与α的趋势不是单调的。对于峰值H _max生成，α出现在90°，而对于峰值D _max，α处于45°至60°的范围内，并且接近50°。至于效率，η随α的增加而缓慢增加，然后随f的增加先增加然后减小。在7 Hz和8 Hz之间的临界值。该发现可能为模仿海豚的豚鼠运动的仿生媒介物设计提供重要的水动力基础。