Statistics of the photospheric velocity swirls detected by ASDA from the numerical simulations. In panels a–c and e–h, swirls with negative (positive) rotations are shown in red (blue), and all swirls are shown in black. N denotes the number of swirls in each frame of the simulation, R the average effective radius, v_r the average rotating speed, I the average normalized photospheric intensity within the area of each swirl, σI the standard deviation of the normalized photospheric intensity of each swirl, the average absolute vertical magnetic field strength of each swirl, and max(|B_z|) the maximum absolute vertical magnetic field strength of each swirl. The green vertical lines in (panels d, e, and g–h) depict a lifetime of 20 s, an average normalized photospheric intensity of 1, and a vertical magnetic field strength of 100 G, respectively.