Fig. 6.
(a) Definition of the physical parameters, characterizing the launch and cratering processes, also used in the calculations. v i , initial ejection velocity; θ i , ejection angle; m i , mass of ballistic ejecta; D, distance; θ f , impact angle; v f , impact velocity; R, radius of the impact crater. (b) P0, initial (explosion) pressure; P a , atmospheric pressure; m s , mass of solid material; m g , mass of gas; ρ a , the density of ambient air; ρ s , the density of solid material at source and r, the distance that solid material has reached, are used in the Fagents and Wilson (1993) model. The dimension of a conical-shaped gas region is characterized by r i , the radius of the conical region; r s , the radius of the conical region plus the solid carapace; r c , the thickness of the carapace; Ω, solid angle of cone; 2θ0, apex angle. (c) Drag coefficients, C d , varying with Mach number for two extreme cases for cubic shape blocks (high- and low-cube). For a high cube, one face is perpendicular to the flow direction, while a low-cube is oriented with a corner at the leading edge. The drag coefficient for a sphere (gray line) is also shown as a reference. Modified from Mastin (2008).