Abstract The hydrodynamic problem of a three dimensional cone entering water in three degrees of freedom is analysed based on the incompressible velocity potential theory. The effect of horizontal motion and rotational motion on the entry process is investigated. The problem is solved through the boundary element method in the time domain. Two physical coordinate systems are constructed. One is the body-fixed system for the solution of fluid velocities and free surface tracking, and the other is the space-fixed system for equations of motion. To match the extremely small wetted surface at the initial stage, the former frame is stretched based on the ratio of physical coordinates and vertical travelled distance. The auxiliary function method is used to decouple the nonlinear mutual dependence between fluid loads and the body motion. Detailed results for cone motion, impact pressure and free surface are provided, and in-depth discussion on the effect of the horizontal motion and rotational motion is given.

中文翻译：

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锥体在三个自由度的自由落体水入口

摘要 基于不可压缩速度势理论，分析了三维锥体三自由度入水的水动力问题。研究了水平运动和旋转运动对进入过程的影响。该问题通过时域中的边界元方法解决。构建了两个物理坐标系。一个是求解流体速度和自由表面跟踪的体固定系统，另一个是运动方程的空间固定系统。为了匹配初始阶段极小的润湿表面，根据物理坐标和垂直行进距离的比率拉伸前一帧。辅助函数法用于解耦流体载荷与身体运动之间的非线性相互依赖关系。