三孤立波的斜坡爬高特征

该文采用推板式造波机和改进的Goring造波方法在波浪水槽中生成了由三个等波高孤立波组成的波列,首先在坡度为1/10的斜坡上进行了多个孤立波连续爬高的实验研究。实验测量了等波高双孤立波和三孤立波在等水深波浪水槽中传播和在斜坡上的爬高过程,给出了沿程多点浪高仪测量的波面时间序列和高速摄像记录的水线在斜坡上爬高与回落过程影像。分析了来波相对波高和无量纲波峰间距对每个孤立波爬高放大系数的影响。在基于RANS方程和VOF方法的数值波浪水槽中,模拟了三孤立波爬高过程,给出了最大爬高与破碎特征。实验和数值模拟结果表明,孤立波在斜坡上回落时会产生强劲的回流水流,该反向流动导致后随孤立波破碎,消耗波动能量,使得后随孤立波的爬高放大系数明显小于没有回落水流影响的首个孤立波的爬高放大系数。当孤立的波峰间较大时,若来波相对波高较小,后两个的孤立波爬高基本相同;若来波相对波高较大时,第三个孤立波的爬高大于第二个孤立波的爬高。

Characteristics of runup of triple solitary waves on slope

A train of triple iso-height solitary wave with third order accuracyis generated in a wave flume by utilizing the modified Goring's method.Experiments on the runup of double or triple solitary wave on a plane beach of 1∶10 slope are conducted first.The propagation and runup of iso-height double and triple solitary wave in the wave flume are conducted experimentally by recording the time series of free surface on several points along the wave flume by wave gauges,and the movements of waterline on the beach by two high speed cameras.The effects of the relative wave amplitude of the target solitary wave and the dimensionless distance between two successive wave crests on the runup amplifications of individual waves are analyzed and discussed.Numerical simulations on the runup process of triple solitary waves are implemented in a numerical wave tank based on RANS equations and VOF method.The maximum runup of solitary waves and their breaking characteristics areanalyzed,too.Because of the existing of washing down flows on the slope beach which account for the successive solitary breaking and energy consuming,both the experimental and numerical results turn out that the runup amplification coefficients of the second or the third solitary wave are significantly smaller than that of the first.For iso-heighttriple solitary waves with great separation distances between contiguous crests and small wave height-to-depth ratio,the runup of the last two solitary waves are almost identical.While for cases with great wave height-to-depth ratio,the runup of the third solitary wave is bigger than that of the second.