Principia Philosophiae Naturalis

The direct, indirect and mediated influence of the books Principia Philosophiae by René Descartes (apud Ludovicum Elzevirium 1644) and Philosophiae Naturalis Principia Mathematica by Isaac Newton (first published on July 5, 1687 and after correction in 1713 and 1726), both in Latin, on all sides of scientific life it is difficult to evaluate and overestimate. The principles of searching for methods for the universal description of natural phenomena (Descartes) and the formulation of direct laws of nature (Newton) are continued to be independently developed and used in various branches of science. Of special interest is the analysis of their application to hydrodynamics, the subject of interest of the both classics, which remains relevant at the present time. Here, in addition to the causality principle in description of the phenomena, constitutive approaches were added. In modern studies, the concepts based on the intuitive inclusion of random components in the flow patterns are actively developing by a large group of authors. In the given talk, the results of theoretical (analytical and numerical) and experimental studies of stratified flows, as well as some observations of the structure of natural systems, are used to compare different classical approaches.