Kolmogorov Universal Law for the Fine Structure

The sizes of the eddies are called scales

1. Large eddies (energy containing eddies) having length scales, say l . For a turbulent channel flow, l~ D, where D is the width of the channel.
   
2. Small eddies (energy dissipating eddies) having length scales , called Kolmogorov length scale.

Each length scale is associated with its corresponding time scale. Smallest length scale has the smallest time scale.

Scales smaller than Kolmogorov scale do not exist. Molecular viscosity dissipates small scale energy into heat.