混合有限分析法求解σ坐标系下的扩散方程

Solutions of diffusion equation under sigma coordinate system by hybrid finite analytic method

用混合有限分析法 ,分别采用σ坐标系下对二阶混合偏导项 3种处理模型 ,模拟了二维垂直平面上具有变化水下地形的封闭静止水域中的浓度扩散问题 ,以检验该方法在σ坐标系下求解对流扩散方程的适用性 .计算结果表明 :(1)混合有限分析法能够很好地求解经过σ坐标变换后的对流扩散方程 ;(2 )

To test the validity for simulating convection_diffusion equations under the sigma coordinate system, the hybrid finite analytic method (HFAM) is applied to solve the salinity diffusion equation, in which the diffusion term has been modelled with three different formulas in a quiescent_sloping basin. The result demonstrates that (1) the HFAM can exactly resolve the convection_diffusion equations that have been converted in the sigma coordinate system; (2) it is necessary to predigest the second_order derivative for getting more accurate simulation pattern by using sigma coordinate converting.