船舶耐波性计算的实用统一理论研究

Research on Practical Unified Theory for Calculations of Ship Seakeeping

采用频域方法计算船舶耐波性的统一理论综合了切片理论和普通细长体理论,能够计入一定的三维效应及在更宽频率范围内计算细长船体的水动力。针对统一理论应用中的匹配积分方程的计算不稳定和耗时较多问题,基于零航速匹配积分核函数的遭遇频率法进行辐射水动力计算,假设绕射势慢变部分满足拉普拉斯方程,提出耐波性计算的实用统一理论,有效避免了数值计算的不稳定并提高了计算效率。与切片理论、三维势流理论的计算结果以及试验值的对比表明,实用统一理论与三维航速修正法的水动力预报精度相当,可满足快速有效的工程计算需求。

The unified theory of frequency domain method for calculating ship seakeeping combines strip theory and ordinary slender ship theory,which can take into account certain three-dimensional effects and achieve hydrodynamics of slender ship in a wider frequency range.In practical applications,the unified theory encounters numerical instability when solving matched integral equations with low computational efficiency.Numerical instability in computing radiation hydrodynamics is solved by using the encounter frequency method based on the zero-speed matched integral kernel function.In which it is assumed that the slowly varying part of the diffraction potential satisfies the Laplace equation and can reduce the computing time.The new improved method is the Practical Unified Theory(PUT).The results of PUT are compared with that of PUT,strip theory,three-dimensional potential flow theory,and experimental data.The comparison shows that PUT has the same accuracy with the three-dimensional speed correction method.It can meet the requirements of rapid and efficient engineering computations.