黄河三角洲海岸冲淤及泥沙输运模型数值模拟分析

Numerical Simulation Analysis of Coastal Erosion and Deposition and Sediment Transport Model in the Yellow River Delta

黄河三角洲是陆海交界地带,陆地海洋相互作用显著,泥沙所引起的岸滩演变、港口航道的淤积、水动力环境的改变等问题比较复杂。该文采用三维HEM-3D数值模型对黄河三角洲海域流场变化、盐度、悬浮泥沙浓度及海岸冲淤分布进行了潮流周期内的数值模拟分析。结果表明,黄河三角洲海域的悬浮泥沙浓度分布与潮流场变化和河口泥沙输入有密切的关系,在三角洲北部受五号桩外强潮流区的影响,近岸海底的泥沙发生明显的再悬浮,并在涨潮流向南输送,含沙量达1.5 g/L左右。在三角洲南部(现行河口区域和莱州湾区域),受现行河口入海泥沙扩散的影响显著。海域年冲淤分布,在北部废弃三角洲区域,由于海洋动力作用强烈,浅水冲刷,海底侵蚀显著,形成了明显呈沿岸展布的侵蚀中心,在侵蚀中心以外,侵蚀快速减弱。在现行河口区域,以淤积为主,在羽状流扩散的控制下,泥沙入海后向南输运,至莱州湾区域逐渐减弱。数值模拟的结果与卫星遥感解译的岸线变化基本一致,效果良好。

The Yellow River delta is the border area of land and sea. The land ocean interaction is significant. The beach evolution, siltation of harbor channel and changes of hydrodynamic environment caused by silt are rather complicated. In this paper, three-dimensional HEM 3D numerical model is used to simulate the flow field, salinity, suspended sediment concentration and coastal erosion and siltation in the the Yellow River Delta. It is showed that the concentration distribution of suspended sediment in the the Yellow River delta is closely related to the change of tidal current and the input of the estuarine sediment. In the north of the delta, the sediment of the near shore seabed is obviously suspended and transported to the south by the influence of the strong flow area outside the five pile, and the sediment concentration is about 1.5g/L. In the southern delta （current estuary and Laizhou Bay area）, the influence of sediment diffusion on the estuary is remarkable. The distribution of annual erosion and siltation in the sea area, in the northern abandoned delta region, because of strong marine dynamic action and shallow water scouring, the seabed erosion is very obvious, and forms the erosion center along the coast. The erosion is rapidly weakened outside the erosion center. In the current estuarine area, siltation is dominant, and under the control of plume diffusion, the sediment transport to the south and then gradually weaken to Laizhou gulf. The results of numerical simulation are basically the same as those of satellite remote sensing interpretation.