摘要
基于高速摄像试验方法,研究了开放空腔壳体的倾斜入水运动特性,重点分析了开放空腔结构引起的空泡流动特征和壳体运动规律.通过试验数据分析了开放空腔内气体运动将引起独特的空泡流动和阶段性的运动规律,探讨了初始入水速度、入水姿态对入水弹道和空泡形态等运动特征的影响.结果表明:开放空腔壳体入水空泡出现阶段波动演化现象,并先后经历两次闭合;入水空泡演化改变流体动力分布,直接影响壳体运动方式,进而改变水下弹道特征;空腔内部形成相对独立流场环境和开放端周期性流动,在重力作用下液体对空腔内下侧壁面作用力较大,加剧壳体偏转,从而改变入水运动过程的稳定性;随着入水速度的增大,空泡波动特征逐渐明显,闭合时间延迟,非对称深闭合引起的横向位移减小,但偏转角度与入水速度无关;随着初始姿态倾角减小,空泡波动程度减弱、闭合时间延迟,偏转角速度增大,闭合引起的横向位移增大.
The objective of this present study is to address the cavitating flowing characteristics and kinetic features in inclined water-entry created by a semi-closed cylinder.For this purpose,based on the high speed camera technology,an experimental study of the inclined water-entry of a semi-closed cylinder are investigated.According to the results of the experiment,the special fluctuation flow pattern form of the semi-closed cylinder cavitation is found around the body and the typical kinetic motion law is gained by analyzing the cavity image data.A further insight into the influence of the initial impact velocity and attitude on the movement characteristics such as water trajectory and cavity shape is discussed.The obtained results show that the cavitation flow pattern form of fluctuation cavitation appears two cavity deep closure successively.The cavity evolution of water entry alerts the hydrodynamic distribution,and then influences the movement pattern of the semi-closed cylinder and trajectory characteristics.The internal flow of the cylinder is relatively independent of the flow filed.Interestingly,a periodic flow occurs at the open end.We also found that the surface pressure on the lower wall of the model is larger,which is related to the stability of the water entry.With the increase of water velocity,the characteristics of cavitation fluctuation are obvious,the closing time is delayed and the lateral displacement caused by asymmetric deepening is reduced,but the deflection angle is independent of the inlet velocity.As the initial attitude inclinationdecreases,the degree of cavitation fluctuationdecreases,the closing time is delayed,boththe deflectionangular velocity and the lateral displacement are increasing subsequently.
作者
路中磊
孙铁志
魏英杰
王聪
Lu Zhonglei;Sun Tiezhi;WeiYingjie;Wang Cong
出处
《力学学报》
EI
CSCD
北大核心
2018年第2期263-273,共11页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金(11672094,51709042),黑龙江省自然科学基金(A201409),哈尔滨市科技创新人才研究专项基金(2013RFLXJ007),中央高校基本科研业务费专项资金(DUT16RC(3)085)资助项目.
关键词
开放空腔壳体
倾斜入水
入水弹道
空泡形态
semi-closed cylinder
inclined enter-water
water-entry trajectory
cavity shape
