基于PFEM的航行器高速入水力学分布特性及被动降载方法研究

The Unmanned Underwater Vehicles (UUV) entry water with high speed is the tendency for the future development of underwater weapons, which can not only decrease the difficulty of its launch but also can shorten the time to attack the enemy. Therefore, how to realize the UUVs entry water under high speed safely and reliably has been become the hot and difficult subject in water entry field. The aims of this project at the UUVs with a diameter of 200mm and water-entry speed greater than 100m/s, which will suffer drastically mechanical environment and the structure damage problems. The numerical simulation and experimental test methods are used to carry out the mechanical distribution characteristics and passive load shedding method on UUVs with high speed during water entry. The numerical model based on particle finite element method (PFEM) was built to get the precise characteristics of water entry impact flow field and the influence of different structural parameters and motion parameters on mechanical distribution of UUVs entry water with high speed. Then the method of structure design based on the combination of head cap to reduce the impact load during the water entry was presented, and the difficulty that combination of head cap matching design problem of strength and brittleness was broken through. And the rules that influence of structure parameters and initial conditions on performance of load reduction were obtained, uncovering load reduction mechanism of the head cap. The corresponding mechanical test of the UUVs into the water was carried out to test the accuracy of the numerical model and the effectiveness of the load shedding method. Through the research of this project, it can provide theoretical and technical support for the further research on similar hydrodynamic problems.

航行器高速入水是水中兵器未来发展的一大趋势，既能降低其投放难度，又可缩短接敌时间。因此，如何实现航行器安全可靠的高速入水一直是国内外研究的热点与难点。本项目针对直径200mm的航行器以大于100m/s的速度入水时力学环境复杂、结构易破损的难题，采用数值模拟和实验测试相结合的方法，开展航行器高速入水力学分布特性及被动降载方法研究，建立基于粒子有限元法（PFEM）的航行器入水复杂流场的数值模型，获得入水冲击流场的精细特征，得到不同结构参数和运动参量对入水时航行器力学分布的影响规律；在此基础上，基于组合头帽建立降低航行器入水载荷的缓冲结构设计方法，突破组合头帽强度与脆性的匹配性设计难题，获得结构参数及初始条件对降载性能的影响规律，揭示其降载机理；开展相应的航行器入水冲击实验测试，验证数值模型的准确性及降载方法的有效性。通过本项目的研究，为进一步开展同类水动力学问题的研究提供理论支撑和技术支持。

航行器高速入水是水中兵器未来发展的一大趋势，既能降低其投放难度，又可缩短接敌时间。因此，如何实现航行器安全可靠的高速入水一直是国内外研究的热点与难点。项目组完成了基于PFEM的航行器高速入水力学分布特性研究、航行器高速入水冲击载荷的被动降载方法研究和航行器高速入水力学分布及被动降载的实验研究等主要研究内容，建立了基于粒子有限元法（PFEM）的航行器入水复杂流场的数值模型，得到了不同结构参数和运动参量对入水时航行器力学分布的影响规律。设计了三种结构的缓冲头帽，研究了缓冲头帽结构和材料参数对缓冲性能的影响，得到了所设计的缓冲头帽在不同入水速度和入水角度下的缓冲性能。建立了完善的航行器入水试验测试方法，基于课题组设计的航行器高速入水试验装置，开展了一系列航行器入水冲击和缓冲试验，揭示了缓冲头帽的降载机理，通过对比仿真和试验结果，证明了计算模型的准确性。通过本项目的研究，为进一步开展同类水动力学问题的研究提供理论支撑和技术支持，对推动我国空投入水武器的发展具有重要意义。