三峡升船机承船厢浅水船波自然频率的研究

Natural Frequencies of Shallow Water Waves in the Ship Reception Chamber of a Ship Lift

采用有限元方法计算三峡升船机承船水厢浅水船波自然频率，从浅水波方程和船体刚性运动方程出发建立两者耦合的有限元矩阵方程，用子空间迭代法求解该矩阵方程的特征值，从而求出浅水船波自然频率。计算包括三种情况：ａ．无阻尼、无船只的水厢；ｂ．有阻尼、无船只的水厢；ｃ．无阻尼、有船只的水厢，计算的结果表明：摩擦阻尼不但会降低波动的振幅，而且会降低波动的自然频率，对低阶模态自然频率的影响比高阶明显；船只在承船水厢内的自由振荡频率比在无界水域的自由振荡频率高。

The natural frequencies of shallow water waves in the Ship receptbn chamber of a ship lift for the Three Gorges project are calculated with the finite element method. With the shallow water equations and ship motion equations,a coupled finite element matrix equationhas been derived.The sub- space iteration method is used to solve the eigenvalue problem andto find the natural frequencies of the water wave in the chamber. Three cases are investigat- ed:1.a chamber with neither ship nor damping;2.a chamber with damping but withoutship;3.a chamber with ship but without damping. Numerical results show that a. Both theamplitude and natural frequencies of the water wave motion are reduced owing to frictionaldamping; b. The natural frequencies of the ship motion in the water chamber are higher thanthose found in the infinite water region.