REDUCTION OF MOTIONS OF AN OFFSHORE STRUCTURE IN WAVES

研究了近海结构物在波浪作用下运动的减小。作用在结构上的波浪力被构成结构一部分的扑翼板的反作用力所抵消。扑板由直流电机主动驱动，该电机由作用在扑板上的激励力信号控制。利用水波的辐射和衍射理论可以计算出扑翼板的最优振荡，并由此确定了控制系统的最优传递函数。为了验证上述理论，在水箱中进行了模型试验。试验结果表明，采用锚链系泊的驳船型海上结构物的横摇运动可减少65%。

A reduction of the motions of an offshore structure in waves is studied. Wave forces acting on the structure are canceled by the reaction of the flapping plates, consisting of a part of the structure. The flapping plates are actively driven by a D.C. motor which is controlled by the signals of the exciting force acting on the flapping plates. Optimum oscillation of the flapping plates could be calculated by the radiation and diffraction theory of water waves, and the optimum transfer function of the control system is also determined from the calculation.To verify the above theory, model tests were conducted in the water tank. 65 % of rolling motions of a barge type offshore structure moored by chains could be reduced in the experiments.