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.
- 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?"