黄河口泥沙异重流的数值模拟

Numerical Simulation of Sediment Hyperpycnal Underflows at the Huanghe Estuary

将已被广泛应用的一维泥沙异重流控制方程推广到平面二维情形 ,构成一组四方程模型 ,并对方程中重要参数的取值作了讨论。而后针对黄河口泥沙异重流的发生和演变受潮相控制的特殊性对其进行数值模拟。在泥沙异重流的基本控制方程中加入了潮汐影响项 ,采用 ADI法对黄河口的潮流控制方程与有潮汐影响的泥沙异重流控制方程进行半耦合求解。

dimensional controlling equations of sediment h yperpycnal underflows are developed based on a 1-dimensional three-equation mo del, which has been used widely recently. This 2-dimensional model includes fou r equations. The key parameters of the two-dimension model are evaluated quanti tatively. In order to simulate numerically sediment hyperpycnal underflows at th e Huanghe Estuary according to their characteristics, we added some tidal factor s, including tidal level and velocity of tidal current to the basic 2-dimension al four-equation model, then the tide-controlling equations and controlling eq uations of sediment hyperpycnal underflows are solved in half-coupling way with ADI(alternating direction implicit) method. The calculating result shows that t ide-phase controls sediment hyperpycnal under-flows at Huanghe Estuary, which emerge at beginning of ebb-tide, then become the most developed while tide is e bbing rapidly. Sediment hyperpycnal under-flows start to decline at beginning o f flood-tide, they vanish finally when tide is rising strongly. There is go od agreement between the calculating result and the measured records.