Grid convergence test: molar fraction of species A along the line y = L_y/2 at the time t = 1. The solid, dashed, dotted, and dot-dashed lines denote the mesh grids N x × N y = 6000 × 2000 , 3000 × 1000, 1500 × 500, and 750 × 250, respectively. The inset enlarges the outlined rectangular region.