Microrotation viscosity effect on turbulent micropolar fluid channel flow

Abstract

Fluids with an internal rigid microstructure, the so-called micropolar fluids, gain significant attention in many industrial, natural, and biological systems. Here, we study in detail the microrotation viscosity effect on turbulent flows by considering an alternative formulation of the Navier-Stokes equation in which the linear and angular momentum is conserved for the fluid and its microstructure, respectively. The case of low-turbulence channel flow with Re = 5600, based on mean velocity, channel height, and the fluid kinematic viscosity, is used to study the effect of polarity. The present results are discussed and compared against the usual channel flow statistics, from Newtonian, dense suspensions with rigid spheres and polymer turbulent flows in similar conditions. It is found that turbulence tends to increase near the wall as micropolar effects get stronger. This enhancement is attributed to a turbulence generation mechanism that seems to be connected with the micropolar stress tensor and is well described by the present model. At the same time, shear stress inclines near the wall, while drag increase is observed throughout the flow regime. © 2021 Author(s).