摘要： 针对结构体入水轨迹预测中普遍存在的计算成本高、响应速度慢等问题，本文提出了一种基于工程算法的快速求解方法，该方法旨在提高计算效率和精度平衡。不同于传统的计算流体动力学（CFD）方法，本文方法基于简化的入水理论、经验公式以及半经验水动力学模型，开发了一种无需大规模求解流体方程的快速预测算法。通过采用纯弹性接触模型和工程优化的计算策略，在保证计算误差小于真实实验值25%的前提下，显著提高了计算效率，将传统CFD方法的小时级计算时间缩短至秒级。测试结果表明，在无需依赖大量数据库或复杂表格数据的情况下，本文方法在误差控制上与机器学习方法及代理模型方法相比具有明显优势，能够快速预测投放体的入水轨迹和姿态，为相关工程应用提供了高效且可靠的方法。此外，本文系统分析了初始速度、海水流速和初始姿态等关键因素对入水轨迹和落点的影响，揭示了初始速度和海水流速对落点位置的影响作用，尤其在高流速条件下，落点位置对于海水流速的敏感性显著增加，指出了投放作业在特定流速条件下的风险。

Abstract: In the context of predicting the water-entry trajectory of structures, the challenges of high computational cost and slow response time are prevalent. This paper presents an innovative rapid solution method based on engineering algorithms, designed to improve the trade-off between computational efficiency and accuracy. Unlike traditional Computational Fluid Dynamics (CFD) approaches, the proposed method leverages simplified water-entry theory, empirical formulas, and semi-empirical hydrodynamic models, thereby developing a rapid prediction framework that obviates the need for large-scale fluid equation solvers. By employing a purely elastic contact model and engineering-optimized computational strategies, the method significantly enhances computational efficiency while maintaining a computational error within 25% of experimental data. This results in a substantial reduction in computation time from the hours required by conventional CFD methods to mere seconds. The test results demonstrate that, without relying on extensive databases or complex tabular data, the proposed method exhibits a distinct advantage in error control when compared to machine learning and surrogate model methods, providing an efficient and reliable solution for the rapid prediction of the water-entry trajectory and attitude of deployed objects. Additionally, this paper systematically analyzes the impact of key factors, including initial velocity, seawater flow speed, and initial attitude, on the water-entry trajectory and landing point. It elucidates the influence of initial velocity and seawater flow speed on the landing point position, with particular emphasis on the increased sensitivity of the landing point to seawater flow speed under high flow-speed conditions, thereby highlighting the risks associated with deployment operations under specific flow-speed scenarios.