Studying Brownian motion by the difference equation, We can find that the partial differential equation describing the Brownian particle motion is a diffusion equation in mathematical physics.

引入差分方程研究布朗运动，会发现极限情况下的布朗运动所遵循的偏微分方程就是数学物理方程中的扩散方程。

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Based on the skew direction difference operator, the implicit skew difference schemes were constructed, and the boundary condition was unified, to solve the diffusion equation.

采用斜向差分算子，建立斜向隐式差分格式，再结合边界条件，对扩散方程进行求解。

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The pressure equation is solved by mixed finite element method, while the concentration equation is solved by finite difference-streamline diffusion finite element method, that is, using SD f.

提出了解不可压缩两相混溶驱动问题的一种新的数值方法，压力方程用混合有限元求解，浓度方程用差分流线扩散方法求解。

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