Taylor microscale

Summary

The Taylor microscale is a length scale of a turbulent flow defined from the ratio of the velocity fluctuations to their spatial derivatives. It is the curvature scale of the velocity correlation function at zero separation. It lies between the size of the large eddies and the Kolmogorov length, and it is not the size of any particular eddies. The Reynolds number $\mathrm{Re}_\lambda$ built with it is the standard way to state how turbulent a flow is in experiments and simulations.