黄河口滨海区冲淤演变与潮流不对称

Morphodynamics and tidal flow asymmetry of the Huanghe River Estuary

涨落潮不对称是河口滨海区流场的重要特征,在泥沙输运和地貌演变过程中扮演着重要的角色。本文基于实测水深地形、沉积物粒度、水文泥沙观测等资料,分析了黄河口滨海区的冲淤变化、泥沙输运和沉积物特征。同时,本文利用Delft 3D模型模拟了黄河口滨海区的流场,并计算了不同条件下涨落潮流速的不对称分布,结合上述分析,探讨了黄河口滨海区冲淤演变的动力机制。结果表明:现行黄河口至莱州湾滨海区相间分布多个淤积和侵蚀中心;黄河口滨海区存在显著的涨落潮流速不对称现象,现行河口外为涨潮优势流分布区,并呈舌状向南部莱州湾方向伸展,而近岸和莱州湾则普遍为落潮主导;黄河口滨海区的冲淤变化很大程度上受涨落潮流速不对称空间分布及涨落潮优势流转换所控制;强北风作用增强和扩展涨潮优势,促使莱州湾淤积和沉积物粗化。

The asymmetry of flood and ebb plays an important role in the process of sediment transport and geomorphological evolution,which is a significant feature of the flow field in estuaries.The erosion and accumulation,sediment transport and sediment characteristics in the Huanghe River Estuary based on the measured topography,sediment particle size,hydrological and sediment observation data were analyzed in this paper.The Delft 3D model was used to simulate the flow field in the Huanghe River Estuary,and the spatial distribution of magnitude differences between flood and ebb velocities under different conditions were calculated.Combining the above,the dynamic mechanism of erosion and accretion in coastal area of the Huanghe River Estuary was discussed.The results show that there are multiple siltation and erosion centers distributed between the active river mouth and the Laizhou Bay.There is a noticeable asymmetry of flood and ebb velocities in the area,and there is the flood dominant area off the active river mouth,extending the Laizhou Bay southward in a tongue shape,while the near shore and the Laizhou Bay are dominated by ebb.The erosion and deposition in the Huanghe River Estuary are largely controlled by the spatial distribution of flow velocity asymmetry and the conversion of dominant flow.The strong north wind strengthens and expands flood-dominance,and promotes siltation and coarsening of sediment in the Laizhou Bay.