Two kinds of flow in a fountain. The water spouted from the four side nozzles moves regularly in stratified and parallel layers is called laminar flow. The water spouted from the middle nozzle is characterized by the irregular and unsteady movement is called turbulent flow. As a complex phenomenon in fluid dynamics, turbulent flow is caused by the combined action of inertia forces and viscous forces. Its unpredictability is one of the major obstacles to solving fluid mechanics problems.