瓯江口滞流点运动规律数值模拟

Numerical simulation of characteristics of motion of stagnation point in Oujiang River estuary

利用MIKE21软件建立瓯江口二维水流数学模型,研究不同径、潮流条件下滞流点位置的移动规律,并结合历史资料,分析了滞流点迁移对河口拦门沙的动力影响。研究表明:径、潮流水动力的改变,会改变滞流点的位置,其移动规律与口门拦门沙浅滩演变有密切关系。径流量较小时,滞流点上溯,在南北口内均形成滞流点活跃的动力平衡带,口外拦门沙冲刷;当径流量增大时,南北口滞流点下移引起拦门沙淤积,但向口外延伸的程度将受到分流比和河床地形的影响。

Based on the MIKE21-Flow model, a two-dimensional flow mathematical model has been established to study the characteristics of motion of a stagnation point under different runoffs and tides in the Oujiang River stagnation point will make appropriate response. And this unique characteristic of motion is in conformity with the evolution of the entrance bar. When river discharge decreases, the stagnation point moves upstream so actively that a dynamic balance zone is formed at both south and north branches, and scouring at the entrance bar occurs. When river discharge increases, affected by the split ratio and the riverbed topography, the stagnation point moves towards downstream with different extensions at the south and north branches, which makes the entrance bar have further deposition. The research results have a great significance in understanding the hydrodynamic changes in the Oujiang River estuary under the influence of the existing works.