极端波浪溢流过程中海堤堤顶的下冲水流特征分析

Feature of downward-flushing flow on crest of levee under combined wave and surge overtopping conditions

针对堤前水位高于堤顶时极端波浪溢流造成的海堤堤顶下冲水流问题,基于波浪溢流大型水槽试验中测得的堤顶流速时间序列开展研究,并提出波浪溢流过程中不同角度下冲水流的发生概率和平均流速的经验公式。结果表明,下冲水流的流速通常大于同一位置的流速均值,下冲水流的发生概率随其角度增大而明显减小,下冲水流的平均流速随其角度的增大而略有减小,但当出水高度趋近于0时,不同角度下冲水流的平均流速均会显著增大。

Aiming at the problem of the downward-flushing flow on the crest of a levee caused by extreme combined wave and surge conditions,the time series of flow velocity measured in full-scale flume tests on combined wave and surge overtopping are investigated,and empirical formulas for the occurrence probability and average velocity of the downward-flushing flow of different angles are proposed.The results show that the velocity of downward-flushing flow is usually greater than the average velocity at the same position.The occurrence probability of downward-flushing flow decreases significantly with the increase of its angle,while the average velocity of downward-flushing flow decreases slightly with the increase of its angle.However,the average velocity of downward-flushing flow of different angles increases significantly when the relative freeboard approaches 0.