2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/105317Equations for correlation functions, here referred to as Reynolds- Kraichnan-Lewis equations (RKLE), are considered and their wide application is indicated. Perturbation and non-perturbation solutions are given. To elucidate a closure problem - various forms of equations are presented. Exact, closed equations for the projected correlation functions are derived.Fluid DynamicsClassical Physicstext