Comparison of the temporal change in the height of the border part of τ = 1 in the ejecta curtain model of the monodisperse particle cases with the measurement data. The line colors (red, green, and blue) correspond to the cases with an ejecta particle size of a_m = 1 mm, 1 cm, and 10 cm, respectively. The thickness of the lines corresponds to the cases with an ejection angle of θ = 60, 45, and 30 deg. The scatter of the model lines comes from the discreteness of the numerical calculation, which moves the position of τ = 1 as slightly as shown.