  Non-Gaussian velocity distribution in star forming region is reproduced by
inelastic clump collision model. We numerically calculated the evolution of
inelastic hard spheres in sheared flow, which corresponds to cloud clumps in
differential galactic rotation. This system fluctuates largely around
equilibrium state, creating clusters with inelastic collisions and destroying
them with shear motion. The fluctuation makes spheres have non-Gaussian
velocity distribution with nearly exponential tail. How far from Gaussian
distribution depends upon coefficient of restitution, which can produce the
variety of degree of deviation from Gaussian among regions.
