`Turbulence is the most important unsolved problem of classical physics.'

- Richard Feynman -

`I am an old man now, and when I die and go to heaven there are two matters on which I hope for enlightenment. One is quantum electrodynamics, and the other is the turbulent motion of fluids. And about the former I am rather optimistic.'

- Horace Lamb -

`Big whorls have little whorls, which feed on their velocity, And little whorls have lesser whorls, and so on to viscosity.'

- Lewis Richardson -

`Turbulent fluid motion is an irregular condition of flow in which the various quantities show a random variation with time and space coordinates so that statistically distinct average values can be discerned.'

- Hinze -

`The necessary connection between the diffusion and the supply of energy to the turbulent motion is a fundamental charactersitic of turbulent flow.'

- Townsend -

`Turbulence is a three dimensional time dependent motion in which vortex stretching causes velocity fluctuations to spread to all wavelengths between a minimum determined by viscous forces and a maximum determined by the boundary conditions. It is the usual state of fluid motion except at low Reynolds numbers.'

- Bradshaw -