系泊方柱在畸形波与波群伴生波浪作用下运动响应试验研究

Experimental study on the motion response of a moored square cylinder under freak wave group

畸形波与波群伴生波浪作用于系泊浮体,和常规随机波浪作用比较,运动响应时频域特征均将发生显著变化。基于物理模型试验,采用小波方法计算伴生波浪和常规随机波浪作用下系泊浮体运动响应的时频域特征变化及波群因子与浮体运动响应时频域特征的定量关系。结果表明:伴生波浪作用下浮体运动响应显著大于常规随机波浪的作用结果,且波群因子G A对浮体运动响应时频域特征有显著影响;伴生波浪作用下浮体纵荡运动的广义能量谱E(t)统计特征值E max(t)、E 1/10(t)、E 1/3(t)、E average(t)均明显大于相同波谱下常规随机波浪的结果,且随着波群因子G A增大显著增大;伴生波浪作用下各运动响应能量集中度δE显著大于常规随机波浪作用结果,且能量集中时域分布范围参数ΔT E以纵荡运动分量最为显著。

The freak wave group has a significant impact on the time-frequency domain characteristics of the motion response of the floater.Based on a two-dimensional model test,the wavelet analysis method was used to calculate the time-frequency characteristics of the motion response of the moored floater under freak wave group and random wave,and the quantitative relationship between the freak wave group factor G A and the time-frequency characteristics of the motion response was investigated.The results show that the time-frequency domain characteristics of the motion response under freak wave group are significantly larger than those under random wave with the same wave spectrum.It is found that the freak wave group factor G A has significant effects on the time-frequency domain characteristics of the montion response.The statistical characteristics of the“generalized energy spectrum”E max(t),E 1/10(t),E 1/3(t),E average(t)of surge are obviously larger than those under random wave and increase significantly with the freak wave group factor G A.The energy concentration degreeδE under freak wave group is also larger than that under random wave and the time distribution parameter of energy concentrationΔT E is mainly reflected in the surge.