长江口南支流场的平面二维有限差分模拟

本文利用二维隐式差分格式和二维特征差分格式对长江口南支流场进行了模拟计算。由于水位变化急剧,地形复杂,计算容易引起局部不稳定。为了增强计算格式抑制非线性不稳定的能力,根据所用格式不同,在动量方程中补充了不同形式的附加虚拟阻尼项。为了适应江心洲和边滩、导堤随潮位涨落时而淹没、时而露出水面而造成的边界的变化,引用了动边界技术。结果表明、潮位、流速和流量过程的计算值无论在量值上和相位上均与实测资料基本吻合、流场的形态合理。

Finite Difference Simulation of Horizontally 2-D Flow Field of Changjiang Estuary

The implicit finite difference scheme and chracteristic difference scheme employed in simulating horizontally two-dimensional flow field of Changjiang estuary.In order to suppress nonlinear instability,we have introduced addditional artificial viscosity of different types in kinematic equations.Moving boundary technique was applied to follow correctly the variation of boundary due to fluctuation in stage during ehb and flood.The results obtained from the computations for both quantity and phase are in satisfactory agreement with the field measurements.In order to improve the navigation condition in the estuary,a dyke which submerges during flood tides and exposes during ebb tides is planned.The flow field is calculated,and the results are also resonable.