The process of low-velocity water entry is utilized on a large scale for the military and engineering purposes. However, there are rarely systematic experimental investigations into the low-velocity water entry of cyl...The process of low-velocity water entry is utilized on a large scale for the military and engineering purposes. However, there are rarely systematic experimental investigations into the low-velocity water entry of cylinder structure for reference. In order to obtain typical phenomena and relevant laws, we design a set of experimental facilities with adjustable parameters and better repeatability to study this process with a high-speed photography system. The influences of cylinder radius, initial velocity and entry angle on the process of lowvelocity water entry are tested. Results show that six typical phases exist in this process: structure submersion,necking, cavity formation, cavity abscission, spray at the free surface and jet formation. Three factors mentioned above are key parameters and influence the process in different degrees, and some laws obtained in this paper have a reasonable agreement with the theoretical results. Our results provide references for the relevant numerical researches and engineering applications.展开更多
研究高速射弹小角度入水过程中的空化现象和弹体运动规律.计算采用VOF多相流模型捕捉空泡界面,采用Schnerr and Sauer空化模型模拟空化现象,弹体运动通过6自由度方程与重叠网格技术进行求解.计算分析了弹体小角度入水过程中的弹道特性...研究高速射弹小角度入水过程中的空化现象和弹体运动规律.计算采用VOF多相流模型捕捉空泡界面,采用Schnerr and Sauer空化模型模拟空化现象,弹体运动通过6自由度方程与重叠网格技术进行求解.计算分析了弹体小角度入水过程中的弹道特性、空泡的演化规律及射弹的流体动力特性,初步探索了高速射弹的小角度入水时产生的弹跳现象.研究表明:此高速运动的旋转射弹在小角度入水时,弹体轨迹和姿态容易发生很大的变化,空泡形态不对称,弹体大面积沾湿导致弹体受到很大的流体动力和力矩,弹体运动失稳产生弹跳翻转现象.分析表明,弹体小角度入水容易沾湿,沾湿对流体动力及其运动姿态有着极大的影响,弹体的不对称沾湿是超空泡射弹失稳的重要原因.展开更多
基金the National Natural Science Foundation of China(No.11402143)the Shanghai Young University Teachers Training Scheme(No.A1-2035-14-0010-18)the Shanghai Ocean University Scientific Research Fund Projects(No.A2-0302-14-300067)
文摘The process of low-velocity water entry is utilized on a large scale for the military and engineering purposes. However, there are rarely systematic experimental investigations into the low-velocity water entry of cylinder structure for reference. In order to obtain typical phenomena and relevant laws, we design a set of experimental facilities with adjustable parameters and better repeatability to study this process with a high-speed photography system. The influences of cylinder radius, initial velocity and entry angle on the process of lowvelocity water entry are tested. Results show that six typical phases exist in this process: structure submersion,necking, cavity formation, cavity abscission, spray at the free surface and jet formation. Three factors mentioned above are key parameters and influence the process in different degrees, and some laws obtained in this paper have a reasonable agreement with the theoretical results. Our results provide references for the relevant numerical researches and engineering applications.
文摘研究高速射弹小角度入水过程中的空化现象和弹体运动规律.计算采用VOF多相流模型捕捉空泡界面,采用Schnerr and Sauer空化模型模拟空化现象,弹体运动通过6自由度方程与重叠网格技术进行求解.计算分析了弹体小角度入水过程中的弹道特性、空泡的演化规律及射弹的流体动力特性,初步探索了高速射弹的小角度入水时产生的弹跳现象.研究表明:此高速运动的旋转射弹在小角度入水时,弹体轨迹和姿态容易发生很大的变化,空泡形态不对称,弹体大面积沾湿导致弹体受到很大的流体动力和力矩,弹体运动失稳产生弹跳翻转现象.分析表明,弹体小角度入水容易沾湿,沾湿对流体动力及其运动姿态有着极大的影响,弹体的不对称沾湿是超空泡射弹失稳的重要原因.