求解土壤溶质运移方程的广义迎风差分法

    General upwind difference method for soil solute transport equations

    • 摘要: 构造了求解土壤溶质运移方程的广义差分格式,对对流项应用了迎风格式,并进行了数值试验及水分和盐分(Cl-)平衡的检验,并与Hydrus软件(普通Galerkin有限元法)的计算结果进行了比较。从数值计算过程和水盐平衡检验的结果来看,应用广义迎风差分格式后,不仅具有较高的精度,计算量少(空间步长可以取得较大)、计算程序实现简单,而且能有效地克服数值弥散现象。特别地,在土表附近积盐量变化特别剧烈的情况下,不加密节点,也没有出现振荡现象。

       

      Abstract: The General Difference Method(GDM) was used to solve the soil solute transport equations, Upwind Schemes was used for the convection term. This method was verified with the water and salt balance and numerical experiments. The results were compared with the calculated results done by HYDRUS software (Galerkin Finite Element Method). From the results of numerical calculation and the validation of water and salt balance, this method is of high-accuracy. It is obvious that the amount of calculation can be decreased and the calculation procedure can be simplified by GDM. Especially the upwind scheme can effectively avoid the numerical dispersion and oscillation even under the condition of dramatic changes of salt contents and without dense nodes.

       

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