中文说明：通过NS方程的变换形式，利用差分方法，解同位网格下的N-S方程，通过速度U，V方向的分量，求出压力值
English Description：
Through the transformation form of NS equation, the difference method is used to solve the N-S equation under the same grid, and the pressure value is obtained through the components of velocity in U and V directions