波浪入射角及地形对浮体水动力学特性影响的有限元分析

  目的  边界元法在海洋工程水动力学中有着广阔的应用前景，为推广边界元法在海洋工程水动力学中的应用，  方法  根据边界积分法建立积分方程，采用参数化单元边界元法对势流问题进行求解，得出流场速度势。对经典算例进行数值计算，与数学解析解比较，并进行误差分析。在二维问题下，分别采用非连续参数化单元和参数化单元边界元法求解势流速度场问题；在三维问题下，采用参数化单元边界元法求解势流速度场问题。  结果  结果显示，在二维问题下，采用非连续参数化单元边界元法求解势流问题具有较高的精度和效率，可以在采用较少单元数的情况下得到较为理想的数值解；在三维问题下采用参数化单元边界元法虽然计算速度较快，并可以得到较好的平均相对精度，但有些点误差较大，需要改进算法或使用其他单元进行求解。  结论  参数化单元边界元法在求解海洋工程势流问题时，数值计算实现过程更简洁，可发展成为求解船舶兴波等船舶水动力学问题的通用方法。

Wave diffraction and radiation by multiple rectangular floaters

  Objectives  The Boundary Element Method (BEM) has broad application prospects in ocean engineering hydrodynamics. In order to promote the application of BEM in ocean engineering hydrodynamics,  Methods  the integral equation is established according to boundary integral method and a parameterized element BEM is adopted. This meta-method solves the potential flow problem and obtains the velocity potential of the flow field. The numerical calculations are performed on the basis of classic examples, the mathematical solutions are compared and error analysis is performed. Under the two-dimensional problem, the discontinuous parameterization element BEM and parameterized element BEM are used to solve the potential flow velocity field. Under the three-dimensional problem, a parameterized element BEM is used to solve the potential flow velocity field problem.  Results  The results show that under the two-dimensional problem, the discontinuous parameterized element BEM is used to solve the potential flow problem with high precision and efficiency, and the ideal numerical solution can be obtained with fewer elements. The parameterized element BEM under the three-dimensional problem is faster in calculation and can obtain better average relative accuracy, but some points have large margins of error and require the improvement of the algorithm or the introduction of another element to be solved.  Conclusions  When the parameterized element BEM is used to solve the potential problem in ocean engineering, the numerical calculation implementation process is more concise and can be developed into a general method for solving the hydrodynamic problems of ships, such as ship motion.