消浪室宽度对可渗明基床开孔沉箱消浪性能影响研究

Study on the effect of the wave-absorbing chamber width on the wave attenuation performance of perforated caisson sitting on the rubble-mound foundation

开孔沉箱是将传统沉箱的前壁开孔,使沉箱前的入射波浪与反射波浪非同相位叠加,达到消能目的。消浪室是开孔沉箱的重要特征结构,其宽度对开孔沉箱的消浪性能具有重要影响。针对可渗明基床开孔沉箱,赋予消浪室宽度以较大的变化范围,开展专项物模试验,研究探讨了在规则波与不规则波作用下,相对消浪室宽度对可渗明基床开孔沉箱前波高反射系数的影响规律,发现反射系数随相对消浪室宽度的增加呈减小—增大—减小的振荡特性,这一发现有别于前人的研究成果,对工程中开孔沉箱消浪室结构的优化设计具有借鉴意义。同时,对试验工况进行数值模拟和解析计算,以物模试验值为标准,评价两种方法在研究相对消浪室宽度对开孔沉箱波高反射系数影响时的规律把握能力及计算精度,对工程中应用这两种方法给出相关建议。

The typical feature of perforated caisson is to subtract several evenly spaced holes from the front wall,which allows waves to partially pass through and enter the wave-absorbing.When the incident waves overlap with the reflected waves with different phases,the wave energy can be greatly reduced.The wave-absorbing chamber is the feature structure of perforated caisson and its width has great effect on the wave attenuation performance of perforated caisson.In the present research,the wave attenuation performance of perforated caisson sitting on the rubble-mound foundation due to the relative wave-absorbing chamber width was studied by physical experiments.It was found that when the relative wave-absorbing width grew,the reflection coefficients in front of the perforated caisson tended to change oscillatory.This finding differs from previous researches and can be used for reference for optimal designing of the structure of the wave-absorbing chamber of perforated caisson.Numerical research and theoretical analysis were also proposed to calculate the reflection coefficients and the results were compared with those from physical experiments.Their capacity for capturing the regularity and calculation precisions were evaluated.Suggestions were then given on using these two kinds of methods in practical engineering.