Perturbation of the planet-induced gas flow on the radial velocity of dust and the dust surface density. We set m = 0.1, ℳ_hw = 0.03, St = 10⁻³, and α_diff = 10⁻⁴. Top: gas flow structure at the meridian plane. The color contour represents the gas velocity in the x-direction averaged in the y-direction within the calculation domain of hydrodynamical simulation, 〈v_x,g〉_y. The vertical dotted lines represent the x-coordinates of the edges of the outflow region, ${\omega }_{\text{out\hspace{0.17em}}}^{\pm }$. Middle: perturbed radial drift velocity of dust. The horizontal dashed line represents v_drift. Bottom: time evolution of the dust surface density. The gray dashed line corresponds to the steady-state dust surface density. The circle and triangle symbols denote the location of the numerically calculated edges of the dust gap and ring.