用MATLAB编写的基于有限体积法求解二维浅水方程边界数值通量的Riemann求解器（HLL格式），可处理干河床问题，适用于规则网格及不规则网格，只需提供边界左右两侧的水深和流速以及外法线矢量-Written using MATLAB numerical flux based on the finite volume method for solving the two-dimensional shallow water equations boundary Riemann solver (HL