Towards Micro-vortices Generated by Liquid Water’s Structural Heterogeneity

Abstract

Abstract Turbulence is a widespread phenomenon detectable in physical and biological systems. Examining a theoretical model of liquid water flowing in a cylinder at different Raleigh numbers, we propose a novel approach to elucidate the first stages of turbulent flows. The weakly bonded molecular assemblies of liquid distilled water form a fluctuating branched polymer in which every micro-cluster displays different density. Against the common view of liquid water as an incompressible and continuous fluid, we consider it as a non-homogeneous, compressible medium characterised by density differences. We suggest that the occurrence of transient local aggregates in liquid water could produce the vortices and eddies that are the hallmarks of turbulence. As in a two-fluid model, lighter fluid interacts with heavier fluid as if one of the two were an obstacle. Micro-assemblies of such obstacles might justify the presence of micro-vortices and hence of turbulence. We quantify the local changes in velocity, diameter and density required to engender obstacles to the average flow. Then, we explain how these microstructures, equipped with different Raleigh numbers and characterized by high percolation index, could generate boundary layers that contribute to micro-vortices production. We explore the theoretical possibility that three-dimensional turbulence might originate from micro-vortices, contrary to the common view that three-dimensional turbulence is caused by energy cascades from larger to smaller vortices. We conclude that the genesis of turbulence cannot be assessed in terms of collective phenomena, rather is sustained, among many other factors, by the underrated microscopic inhomogeneities of fluids like liquid water.