潜堤对平均沿岸流及沿岸流不稳定的影响

潜堤是防止海岸侵蚀的常用护岸建筑物,准确的掌握潜堤前后水动力特性十分必要.本文以斜坡上梯形潜堤为研究对象,基于港池沿岸流实验,通过变换潜堤的位置来分析潜堤对平均沿岸流的影响,通过增加潜堤来观察其对沿岸流不稳定波动频率的影响.结果表明,潜堤离岸越近,垂直岸方向的沿岸流分布有向岸偏移的趋势,同时,会使得沿岸方向上游流速增加越大,使总的沿岸方向的流速分布更均匀;增加潜堤会使沿岸流不稳定某些频率的波动明显加强,同时也会使沿岸流不稳定波动出现新的高频部分.

Influence of submerged breakwater on the mean longshore currents and the instability of longshore currents

Submerged breakwater is a kind of commonly used maritime sheltering structures, so it is necessary to accurately grasp the hydrodynamic characteristics before and after the submerged breakwater. Based on the longshore current experiment in harbor, taking the trapezoid submerged breakwater as the research object, this paper analyzes the influence of submerged breakwater on the mean longshore current by changing the position of submerged breakwater and observes the effect of submerged breakwater on the instability of longshore currents for frequency fluctuation. The results show that the closer the submerged breakwater, cross-shore longshore current velocity has the more obvious tendency to toward the shore. Meanwhile, it will make the upstream direction of longshore current velocity increase and will make the distribution of longshore current velocity in the direction of the whole coast is more uniform. Furthermore, some frequency fluctuation of longshore current instability may strong and new high frequency components of the instability of longshore currents may occur for the increase of the submerged breakwater.