Turbulence

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.

Examples of turbulence

• A faucet[?] goes from
  • Off. No flow
  • Drip. Which would be modeled as a free boundary problem[?]
  • 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.
• A drop of cream in a cup of coffee.
• Smoke from a smokey candle.

Anecdote: ,a famous scientist was asked what he would ask God, given the opportunity. His laconic reply was: "Why turbulence?"

See also

• Downdrafts
• Fluid mechanics
  • Navier-Stokes equations
  • Poiseuille's law
  • Darcy-Weisbach equation
• Mesocyclones
• Vortex

External Links

• [Center for Turbulence Researce (http://ctr.stanford.edu/)], Stanford University
• Journal of Turbulence (http://www.iop.org/EJ/S/UNREG/journal/1468-5248/1) - Institute of Physics (http://www.iop.org/)
• What is Turbulence (http://www.uncarved.demon.co.uk/turb/what.is)
• http://turb.seas.ucla.edu/~jkim/sciam/turbulence - Scientific American article