The distribution of particle concentration in pipe is unequality and the unequality degree varies with the cent of volume and regimeflow;
颗粒在管内的浓度分布是不均匀的，随颗粒的体积分率和流型的变化而变化；
2
The way the flow transitions from one regime to another is hugely complex but a number of models, in particular those using cellular automaton, have become useful in studying how it occurs.
Some way into its path - perhaps around the 10 m mark (or at about the position of the wall of defenders) - the ball's velocity dropped such that it entered the laminar flowregime.