不规则波情况下沿岸流不稳定运动传播方向的研究

A study on the propagation direction of the unstable motion of longshore currents under the irregular waves

本文以沿岸流不稳定运动实验中流速仪采集到的不规则波的流速时间历程为基础,利用相关性分析,得到两个不同位置处对应流速时间历程的最大相关系数和延迟时间,进而分析沿岸流不稳定运动在1∶40和1∶100平直斜坡上的传播方向,并且分析了其随入射波高、周期的变化。结果表明沿岸流不稳定运动在海岸垂向环流系统的作用下,其传播方向会向海方向偏移,与岸线角度大约在0°到45°之间,且在1∶40和1∶100坡情况下,沿岸流不稳定运动的偏移角分别随入射周期和波高的增加而增加,但1∶100坡的增加幅值较小,大约为1∶40坡情况下的1/2。

Based on the time history of flow velocity of the irregular waves gathered from current meters in the experiment of the instability of longshore currents and using correlation analysis, the max correlation coefficients and delayed time of two different positions were gained in this article, and then the direction of propagation was analyzed in two kinds of flat slopes which had the slope of 1 ： 40 and 1 ： 100 of the instability of longshore currents, and its change along with the change of incident wave height and period was analyzed. The results showed that the propagation direction of the instability of longshore currents had a shifting to the sea direction under the vertical coastal circulation system, with the angle of about 0° to 45°. And in the cases of 1 ： 40 and 1 ： 40 slopes, the deviation angle of the unstable motion of longshore currents will increase respectively with the increasing of incident period and wa,~e height; and in the 1 ： 100 slope, the increase amplitude of the deviation angle of the unstable motion of longshore currents is smaller, about half of that in the 1： 40 slope.