Velocity profiles in the shock region at the end of the simulation (T_max = 2400) in the four cases; the vertical solid and dotted lines indicate the shock front and FEB in each plot, respectively; the horizontal solid, dotted, dot-dashed and dashed lines show the values of the shock velocity v_sh, velocity of box frame v_box, subshock velocity v_sub and initial bulk velocity U₀, respectively. Two vertical bars in each plot represent the two deflections of velocity, the upper bar represents the part of the shock precursor and the lower one represents the subshock.