Abstract In this paper, experimental and numerical studies were performed to investigate the characteristics of longshore current under two mild slopes, the results of which may complement the existing studies, which have mainly focused on steep slopes. The experimental results revealed that the average velocity distribution of the longshore current was significantly different under the two different mild slopes. Under the slope of 1:100, the distribution of the averaged longshore current velocity had a downward concave trend at the nearshore side, while under the slope of 1:40 the trend became convex. In addition, the analysis of the numerical results showed that the distribution of the averaged longshore current velocity was affected by the distribution of the wave height within the surf zone and the bottom friction equations, with the influence of the latter being more significant. For the slope of 1:100, the cross-shore variability of alongshore variability can be calculated using the flow-type bottom friction equation, while for the slope of 1:40, the wave-type bottom friction equation can be used instead. Finally, the secondary breaking wave heights for mild slopes and the distribution of wave set-up are also shown in the study.

中文翻译：

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缓坡平均岸岸流试验研究与数值模拟

摘要 本文通过实验和数值研究，研究了两种缓坡下沿岸流的特征，其结果可以补充现有的主要集中在陡坡上的研究。实验结果表明，在两种不同缓坡下，沿岸流的平均速度分布存在显着差异。在1:100斜率下，近岸平均岸流速度分布呈下凹趋势，而在1:40斜率下，趋势呈凸形。此外，对数值结果的分析表明，平均岸边水流速度的分布受冲浪带内波高分布和底部摩擦方程的影响，后者的影响更为显着。对于1:100的坡度，可以使用流动型底部摩擦方程来计算沿岸变异的跨岸变异，而对于1:40的坡度，可以使用波浪型底部摩擦方程来计算。最后，研究中还显示了缓坡的二次破碎波高和波浪设置的分布。