裂流垂向分布实验研究

通过物理模型实验给出了沙坝海岸丁坝附近交叉波浪场形成的裂流沿裂流槽水深平均速度剖面中心线的垂向分布，研究了各个测量断面上横向速度、纵向速度以及速度矢量沿水深的分布特征。研究分析了沿岸方向驻波节腹点和裂流槽相对位置的影响以及规则波和不规则波结果的差异，得到了裂流速度时均值和时变值的结果。结果表明，纵向速度在不同的时间段上的平均值基本是相同的，但横向速度不是这样，其在不同时间段上的平均值在大小和正负号上都可能存在较大差别，这导致整个速度矢量在不同时间段上也表现出不同的三维分布特征。但这些不同的分布也存在着共同点，即沿水深速度矢量大部分存在着向丁坝方向偏转，这反映了丁坝存在的影响。特别是，纵向速度沿水深分布都可以采用统一的幂函数表达。

Experimental study on vertical distribution of rip current

The vertical distribution of rip current formed by the cross wave field near a groin is studied through the physical model experiment with regular and irregular waves and the characteristics of the distribution for transverse, longitudinal velocities and velocity vector at each measurement section are examined. The measurement is along the center line of the depth-average velocity profile in the rip channel. The influence of the position of the node and antinode point relative to the channel centerline is considered. The results of time-average and time-dependent values of rip curent velocity are analysed, and it is found that the longitudinal velocity has stable mean values for different lengths of time spans considered, but this is not the case for the transverse velocity. Due to the effect of rip current instablity, the latter has different mean values for different lengths time spans. This leads to different three-dimensional distribution characteristics of velocity vector over different time spans. However, there are some common points among the results of the different time spans, this includes, most of the velocity vectors at measurement sections deflect towards the groin, which reflects the influence of the groin; the vertical distribution of longitudinal velocity at different measurement sections all follow the power law.