座头鲸虽然体型庞大但仍灵活敏捷，研究表明其非凡的运动能力和其胸鳍前缘上分布的突节有关，这些突节类似于涡发生器，具有增升减阻等作用。事实上，前缘突节流动被动控制方法也可应用在海洋工程装备的水动力学控制面上。水下滑翔机的滑翔速度通常很低，此时低雷诺数来流将会引起水翼严重的流体分离，从而降低其水动力学性能。本项目将通过此前缘突节来改善滑翔机水翼的升阻力性能。.项目利用雷诺数相似原理，通过低速风洞测力天平、高速时间解析粒子图像测速法和流动显示等技术，将研究：.• 静态俯仰角、动态俯仰、偏航和横滚运动、突节形态、雷诺数、翼型和机翼形状等，对水翼升阻力性能以及剪切层和背风区涡脱落特性的影响；.• 静态条件下，周期性流体分离的形成机理；.• 动态条件下，前缘突节对动态失速涡形成与发展的影响。.项目将提出一种水下滑翔机机翼的建议设计方案，使其具有较优的水动力性能和流动分离控制特性。

Although the size of the humpback whales is huge, they are capable of performing complex underwater maneuvers. Recent research shows that this has been attributed to their pectoral flippers, where several tubercles are distributed along the leading-edge. These leading-edge tubercles act as vortex generators, which can enhance the lift and reduce the drag. In fact, this passive flow control technique by using leading-edge tubercles can be applied on the hydrodynamic lifting surfaces of the ocean engineering devices. The underwater glider always works with lower velocities, and the hydrofoils in the corresponding lower Reynolds numbers flow are prone to flow separation, which can lead to poor performance of the hydrofoils. This project aims to improve the hydrodynamic performance for the hydrofoils for the underwater gliders through the passive flow control technique of leading-edge tubercles..Based on the similarity principle in fluid dynamics, the present project will be conducted in a low speed close-circuit wind tunnel. By using force balance, time-resolved particle image velocimetry (TR-PIV) and flow visualization techniques, this project will investigate:.• Effects of static pitch angles, dynamic pitch, roll and yaw, tubercle configurations, Reynolds numbers, airfoils and wing profiles on the hydrodynamic characteristics, as well as vortices shedding characteristics in the shear layer and flow separation region;.• Mechanism of the periodic flow separation for tubercled wings tested under static flow conditions;.• Effect of the leading-edge tubercles on the formation and evolution of the dynamic stall vortex for the tubercled wings tested under dynamic flow condition..Through this project, a tubercled wing configuration design for the underwater glider with the optimum hydrodynamic performance and better flow separation control behaviour will be presented.