In fluid dynamics Turbulence or Turbulent flow is a flow regime characterized by low momentum diffusion, high momentum convection, and pressure and velocity variation with time. Flow that is not turbulent is called laminar flow. The (dimensionless) Reynolds number characterizes whether flow conditions lead to laminar or turbulent flow.
If you consider the flow of water over a simple smooth object, such as a sphere, at very low speeds the flow is laminar; i.e. the flow is smooth, and the drag is realtively low. As the speed increases, at some point the transition is made to turbulent ('chaotic') flow, where there is a large increase in drag, and often vortices behind the object. The same transition occurs if you gradually increase the size of the object or the viscosity of the fluid.
|Table of contents|
2 See also
3 External Links
Examples of turbulence
According to an apocryphal story, Werner Heisenberg was asked what he would ask God, given the opportunity. His reply was: "When I meet God, I am going to ask him two questions: Why relativity? And why turbulence? I really believe he will have an answer for the first."