沿岸流研究对海岸工程具有重要的应用价值。为了更深入地研究沿岸流特征，文章对1∶100和1∶40两个较缓坡条件下的沿岸流进行了实验研究，弥补了现有实验研究主要针对较陡坡情况，不具有代表性的弊端，并通过数值模拟进一步阐述了缓坡情况下的平均沿岸流不同于陡坡情况下的物理机理。主要特色与创新有：第一、通过物理模型实验研究发现了1∶100坡度地形条件下存在不同于1∶40坡度情况下的平均沿岸流速度分布特征：前者海岸一侧平均沿岸流分布呈下凹趋势，而后者呈上凸的趋势。第二、通过平均沿岸流数值模型对1∶100和1∶40缓坡沿岸流的不同特征进行数值模拟，找出了影响平均沿岸流速度剖面特征的主要因素为破波带内波高分布和水底摩擦力表达式的选取不同，且对后者更为敏感。1∶100坡度海岸沿岸流速度剖面可由水流型水底摩擦力来计算出，而1∶40坡度海岸沿岸流速度剖面可由波浪型水底摩擦力来计算出。第三、在此基础上进一步给出了缓坡情况下二次破碎波高和波浪增减水的分布特征。%It is of significant importance for longshore current study to coastal engineering. To further study the characteristics of longshore current, this paper makes experiments for slope 1∶100 and 1∶40, this over-comes the drawbacks of the present study which mainly focuses on steep slopes. Furthermore, the physical mechanism of the differences of longshore current for slope 1∶100 and 1∶40 is elaborated through numerical simulation. Main features and innovations are as follows: (1) It is found by the physical model experiment that there are different characteristics of the distribution of mean longshore current between the condition of slope 1∶100 and 1∶40. The distribution of mean longshore current along the coast of the former has a downward trend; the latter has a convex trend. (2) This paper finds by numerical simulation that the main factors of influencing the mean alongshore current velocity profile are the distribution of wave height and the selection of bottom friction in the surf zone, and the latter is more sensitive.The velocity profile of long-shore current for slope 1∶100 can be simulated by using the flow bottom friction coefficient while for slope 1∶40 can be simulated by using the wave bottom friction coefficient. (3) This paper gives the characteristics of wave height and wave setup at the condition of secondary breakup for mild slope.
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