Velocity dispersion as a function of time. Each panel displays the time evolution of gas above a certain density threshold, from n_H = 10 to 10⁶ cm⁻³. The non-colliding case is represented by dashed lines, while the colliding case is represented by solid lines. For each model, σ_v (averaged over the x, y, and z lines-of-sight) for the total gas content (black), |$\rm {CE_{2}}$| (blue), |$\rm {CE_{3}}$| (green), |$\rm {CE_{4}}$| (red), and |$\rm {CE_{5}}$| (cyan) is plotted.