针对跨介质飞行器入水及出水关键问题的翠鸟捕食行为仿生研究

Aiming at the key problems of water entry and water exit of the aquatic unmanned aerial vehicles (AquaUAVs), the current project carries out the bionic fundamental research on the predation behavior of kingfishers. The specific contents are as follows. Aiming at the selection of the aerodynamic/water configuration and the wing shape-changes when AquaUAV crosses interface of the different media, the size of each part of kingfisher and their relative relations and the relationship between the speed, the attitude and the across interface timing are measured and analyzed, the bionic parameter model of kingfisher and the kinematics model of each part of kingfisher. In order to reduce the water impact and improve the stability of water entry, the changes of the water impact load and water response, and water wetting, spreading and detaching on the substrate of the feather are focused on, and the mechanism of water entry load being released caused by coupled effect of the mode of water entry, the form, flexibility of the feather, and the surface characteristic of the feather surface is revealed as well. To resolve the problems of water exit policy and drag of AquaUAV, the water exit load of the model, the changes of the liquid free surface and the coupling between fluid and solid are investigated. With the characteristic of water detaching from the feather, the mechanism of the water exit of the kingfisher will be obtained. The research project can not only enrich the content of the bionics, but also provide a theoretical support to the technology of water entry and water exit of the AquaUAV, which has great academic significance and application prospect.

本项目针对跨介质飞行器入水及出水关键问题，开展翠鸟捕食行为的仿生基础研究，具体为：针对跨介质飞行器穿越界面时气/水动布局设计及机翼变化策略问题，测量分析翠鸟各部位尺寸及相对关系和入水及出水时速度、姿态与跨界面时机的关系规律，建立翠鸟参数化仿生模型以及入水及出水过程中各部位的运动学模型；为减小跨介质飞行器入水冲击力并提高入水稳定性，分析翠鸟仿生模型入水过程中的冲击载荷变化、水体动力响应及水在羽毛表面的润湿、铺展及脱离特征，揭示入水方式、形体结构、羽毛柔性及表面特性等多种因素对其入水载荷的耦合缓冲机制；为解决跨介质飞行器出水策略及出水阻力问题，研究翠鸟模型出水时出水载荷及自由液面变化、流固耦合等科学问题，结合水在羽毛表面的脱离特性，揭示翠鸟快速脱出水面的功能原理。本项目的开展不仅能丰富仿生学的内容，还为跨介质飞行器入水及出水技术提供理论支撑，具有重要的学术意义和广阔的应用前景。

变体跨介质仿生无人飞行器是一种可在空中与水中两栖巡航并能自由穿越水气界面的新概念海空两栖无人飞行器，可从水下、舰艇或陆地发射，具有作战用途广、隐身性能好、机动能力强等特点，具有重要的军事应用前景。本项目针对跨介质飞行器设计制造所必须突破的入水及出水技术，系统开展了如下工作：分析了翠鸟入水捕鱼过程的飞行姿态，测量翠鸟几何形态，构建翠鸟俯冲及入水姿态的物理模型；采用风洞试验及数值模拟的方法，分析了翠鸟入水前俯冲的气动特性与飞行受力状态；设计并制造了翠鸟/飞行器以不同角度、不同速度入水试验台，可实时测量入水过程中模型轨迹、模型所受冲击载荷及水体响应，应用该试验台和基于VOF的数值模拟，分析了翠鸟及飞行器模型在入水过程中的运动和动力特性及自由面的变化；自行搭建了模拟羽毛弹性及动运动的试验装置，通过试验以及基于LBM数值模拟，定量分析了羽毛弹性作用、运动作用对羽毛脱水性能的影响，解释了翠鸟等水鸟在水中飞行不湿的功能原理，也为跨介质航行器超疏水表面快速掉附连水载荷提供了重要的理论支撑。完成了以上基础研究后，开展了跨介质飞行器流体动力外形设计及流体动力学分析、跨介质航行器变体结构设计及驱动技术、跨介质航行器动力系统、航行器飞行控制系统总体设计研究，制造了跨介质飞行器原理样机，并完成了功能测试。本项目系统研究了翠鸟捕食过程中入水及出水功能原理，并在跨介质飞行器设计与制造上取得了阶段性进展，受到了国防科技部门及航天科技集团的关注，具有重要的军事应用前景。