In this study, hydrodynamic forces on a submerged vessel maneuvering near a free surface are determined using a reformulated Lagrangian nonlinear maneuvering and seakeeping model derived using Lagrangian mechanics under ideal flow assumptions. A Lagrangian mechanics maneuvering model is first reformulated to simplify the computation of parameters; then, incident wave effects are incorporated into the reformulation; finally, the parameters are computed using a medium-fidelity time-domain potential-flow panel code. Predictions from the reformulated Lagrangian nonlinear maneuvering and seakeeping model, whose parameters are computed using the methods described here, are compared with direct numerical computations in two steps for a prolate spheroid maneuvering in the longitudinal plane near the free surface. First, the hydrodynamic force and moment predicted by the model are compared with solutions from the panel code for sinusoidal motion in surge, heave, and pitch in calm water. Second, the hydrodynamic force and moment are investigated for cases where the spheroid maneuvers to approach the surface in calm water and in plane progressive waves. To conclude, a physically intuitive formulation of the Lagrangian nonlinear maneuvering and seakeeping model is presented for control applications and simulations.

中文翻译：

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一种计算水下船舶运动拉格朗日非线性操纵和适航模型参数的方法

在这项研究中，在理想流动假设下使用拉格朗日力学导出的重新制定的拉格朗日非线性操纵和耐波模型，确定了在自由表面附近操纵的水下船舶上的水动力。首先重新制定拉格朗日力学机动模型以简化参数计算；然后，将入射波效应纳入重新制定；最后，使用中等保真时域势流面板代码计算参数。将重新制定的拉格朗日非线性机动和耐波模型的预测与自由表面附近纵向平面中长球体机动的两步直接数值计算进行比较，该模型的参数是使用此处描述的方法计算的。第一的，将模型预测的水动力和力矩与静水中涌浪、升沉和纵摇中正弦运动的面板代码解进行比较。其次，针对球体在平静水中和平面前进波中机动接近表面的情况，研究了水动力和力矩。总而言之，拉格朗日非线性机动和耐波模型的物理直观公式被提出用于控制应用和模拟。