Turbulence or Turbulent flow is a flow regime characterized by low momentum diffusion, high momentum convection, and pressure and velocity variation with time. It is opposed by laminar flow. The (dimensionless) Reynolds number characterizes whether flow conditions lead to laminar or turbulent flow.
Laminar flow. A smooth and regular flow which looks somewhat solid because the flow maintains a fixed shape. In this regime, the water acts as a transparent lense.
Turbulent flow. At a certain point the water will start to break up. The water no long stays contained in a stable region is space. The stream ceases to be transparent.
... census of 2000, there are 19,701 people, 6,700 households, and 5,011 families residing in the town. The population density is 1,549.2/km² (4,010.1/mi²). There ...