长江口斜压诊断模式三维流场数值模拟

3-D current numerical model for the Yangtze River estuary with baroclinic-diagnosis mode

建立了σ坐标系下长江口斜压诊断模式三维流场数学模型,采用k kl二方程紊流闭合模型求解垂向涡粘系数,计算域内恒定、非均匀盐度场反映了计算域密度斜压效应。验证结果表明,斜压诊断模式的模拟成果较切合实际。模型成功复演了长江口水域由往复流向旋转流过渡的流场特性;潮波从四条汊道传入后在分汊口附近相遇形成多个会潮点,其位置随着径流的大小、潮汐的强弱、汊道的形态等因素而变化。

This paper presents a 3-D current numerical model for the Yangtze River estuary with baroclinic-diagnosis mode in vertical σ coordinate system. A vertical eddy-viscosity coefficient is obtained from the advanced k-kl turbulence closure model, and the density baroclinic effects are embodied by the 2-D invariable-uneven salinity field. It shows the results from baroclinic-diagnosis mode well consistent with reality. The transition feature from back and forth current to rotary current is re-acted successfully. In addition, several tidal junction points appeare near branch points when tidal wave propagate from four river forks, the position of which change with runoff, tide and topography.