Comment on Dynamical implications of block averaging by G. Trevino and E.L Andreas

A 2006 article in Boundary-Layer Meteorology by G. Treviño and E.L Andreas presents a derivation that questions the use of time averaging for computing turbulence statistics. Their derivation shows that time averaging over a finite interval always leads to a zero integral time scale. As a result, Treviño and Andreas argue that any turbulence quantities derived from time averaging are tainted and incompatible with the Navier–Stokes equations. While Treviño and Andreas are correct that time averaging does produce integral scales that are quite different from what researchers commonly expect, this comment demonstrates that the theoretical implications are not as dire as they claim.