Germano, M. (1992). Turbulence: the filtering approach. Journal of Fluid Mechanics 238: 325–336. doi:10.1017/S0022112092001733.

Not read. The summary is drawn from the abstract or from what the work is standardly cited for. A reading should check it first.

Why this is here

A3 used it for a distinction the record lacks a word for: a hierarchy of filtered descriptions can exist with no closed equation at any level. Bears on QUESTION-222.