Experimental study on wave pressure distribution of the twin-plate breakwater under freak waves
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摘要: 基于物理模型试验，考虑畸形波参数、相对板宽、相对波高等影响因素，就畸形波对平顶双层水平板防波堤作用进行研究。首先对畸形波作用下双层水平板的波浪力分布特征进行了讨论，然后就最大波动压强、结构最大总垂向力与不规则波作用进行了对比分析。结果表明，畸形波作用下，双层水平板最大波动压力出现在前端迎浪区域附近，向尾端逐渐递减。双层水平板4个受力面的压力分布不同且有相位差，4个受力面的最大波动压力时间差约在0.1Tp~0.4Tp范围内变化。与不规则波作用比较，畸形波作用没有显著改变波压包络分布特征，但增大了波压包络强度值。试验范围内，就最大总力而言，两者最大总浮托力比值在1.06~2.45间变化；向下的最大总垂向力比值在1.22~2.07之间变化；就波动压力而言，其增大的幅度与畸形波参数α1相关性最强，随α1的增大而增大，在α1=2.04~3.1试验范围内，畸形波作用时的最大压强比不规则波作用时可约增大20%~80%。就最大波吸力而言，两者的比值与畸形波参数α4相关性最强，随α4的增大而减小。在α4=0.62~0.75试验范围内，最大波吸力强度的比值在1.61~0.87范围内变化。当α4≤0.72时，畸形波作用时的最大波吸力大于不规则波作用时的最大波吸力；当α4 > 0.72时则刚好相反。Abstract: This study carried out extensive experiments to investigate the wave loads on the twin-plate breakwater under freak waves. The characteristics of wave forces were checked under various relative plate width, relative wave height as well as freak waves parameters. The results show that the maximum wave pressure occurred on the offshore side of the twin-plate, and decreased along the wave propagating direction. The wave pressures on the four surfaces of the twin-plate showed significant difference in both magnitude and phase, and the phase difference ranged in 0.1Tp~0.4Tp. In addition, the measured maximum wave pressure and total vertical force on the twin-plate were compared to those under irregular waves. There is no significant difference in the distribution of the wave pressure envelop for irregular and freak waves. However, the magnitude under freak waves is significant larger than that under irregular waves. Basically, the ratio of the maximum total uplift forces for under freak waves to irregular waves ranges in 1.06-2.45; the ratio of the maximum downward vertical force ranges in 1.22 to 2.07. The increment of the maximum wave pressure is subjected to the freak waves parameter α1.With α1 from 2.04 to 3.1, the maximum pressures under freak waves can be 20% to 80% larger than those under irregular waves. The ratio of the maximum wave suction force between the irregular and freak waves is decreased with α4. With α4=0.62-0.75, the ratio of the maximum wave suction force changes from 1.61 to 0.87. It should be noted that, the critical value of α4 turns out to be 0.72, below which the maximum wave suction forces under freak waves are larger than those under irregular waves, and above which is the other way round.
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Key words:
- freak wave /
- twin-plate breakwater /
- wave loads /
- model test
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