Laminar and turbulent flow

The spinning ball above, is in a smoke chamber. Flow from the left above the ball is laminar - flow at the lower right is turbulent.

At very low speeds, fluids (air, water etc.), flow over a smooth surface in a regular layered pattern as shown above the spinning ball. This type of regular flow is called laminar (layered). Under conditions of laminar flow drag is described by Stokes' law.

> More

At some critical speed, the laminar flow breaks up into a series of complex and often unpredictable eddies known as turbulence. Turbulence is complex and very difficult to model.