淹没垂直圆柱垂荡问题的解析研究

Analytical Solutions of Heave Problem by a Submerged Cylinder

利用匹配特征函数展开法进行了有限水深淹没垂直圆柱垂荡辐射问题的解析解,研究了淹没深度、相对厚度及水深对圆柱水动力系数的影响,结果表明,在大多数频率下,淹没圆柱的附加质量总是大于同样大小的漂浮圆柱,且在高频段近似为漂浮圆柱附加质量的两倍。当淹没深度较大时,圆柱附加质量趋向于常数,辐射阻尼趋向于零。圆柱厚度对水动力系数的影响较为复杂,在不同的频率范围内呈现不同的特征。当水深较浅时,淹没圆柱附加质量随着水深的增加而减小,辐射阻尼受水深的影响则始终不显著。

By means of the method of eigen-function expansion-matching for velocity potential,an analytical solution is developed for heave radiation problem by a submerged vertical cylinder in finite water depth.Numerical examinations show that added mass of submerged cylinder may be larger than that of the floating cylinder.It seems to have a twice relationship at high frequency range.If submerged depth is large,added mass tends to a constant,and radiation damping approaches to zero.The influence of cylinder length on hydrodynamic coefficients is quite complex.It shows different characters in different frequency.Added mass decreases with the increase of water depth if water depth is small,but radiation damping has no evident effect by water depth.