跨介质航行体入水瞬间会受到巨大的冲击载荷,极易导致结构破坏甚至内部器件失灵.为发展有效的降载方法,本文基于VOF(Volume of Fluid)多相流模型,研究头部喷气航行体入水过程的载荷特性和流体动力特性,分析喷气压力、喷气高度对降载效果的影响,并探索头部喷气降载方法有效性的入水速度范围.研究结果表明,头部喷气使自由液面下凹形成空腔,并能极大地降低航行体所受阻力和冲击力,延缓了航行体撞水时间,从而实现冲击载荷控制;喷气压力和喷气高度对入水空泡形态及冲击压力峰值的影响都不大,合理的选择既能达到降载效果又能节约喷气量;入水速度为50 m/s时,降载量高达76.51％,但当入水速度为300 m/s时,降载量仅为39.92％.因此,针对高亚声速跨介质入水问题,需进一步探索主被动相结合的复合降载方法.
Effect of head jet on load characteristics of a transdielectric vehicle during water entry
Cross-media vehicles are subjected to huge impact loads when they enter the water,which can easily lead to structural failure and even internal device failure.In order to develop an effective load shedding method,this paper studies the loading characteristics and hydrodynamic characteristics of the head jet vehicle entering the water based on the VOF(volume of fluid)multiphase flow model,analyzes the influence of jet pressure and jet height on the load shedding effect,and explores the entry velocity range of the effectiveness of the head jet load shedding method.The results show that the head jet concaves the free liquid surface to form a cavity,which can greatly reduce the resistance and impact force of the vehicle,delay the collision time of the vehicle,and realize the impact load control.The jet pressure and jet height have little effect on the bubble form and impact pressure peak,and a reasonable choice can not only achieve the load reduction effect but also save the jet volume;When the water entry speed is 50 m/s,the load reduction capacity is as high as 76.51％,but when the water entering speed is 300 m/s,the load reduction capacity is only 39.92％.Therefore,in view of the problem of high subsonic cross-media water ingress,it is necessary to further explore the composite load reduction method combining active and passive.
万方数据
维普
