The use of eddy viscosity expressions for predecting velocity profiles in Newtonian, non-Newtonian and drag-reducing turbulent pipe flow

Abstract

An understanding of turbulent pipe flow is of extreme importance in engineering. The eddy viscosity concept has been used by many workers to describe fully developed, Newtonian, turbulent pipe flow. A knowledge of the eddy viscosity can then be used to predict mean velocity and temperature profiles (and hence heat transfer coefficients). In addition to the Newtonian case, there are many instances when the turbulent flow of non-Newtonian and drag-reducing fluids are encountered. Although several workers have proposed eddy viscosity expressions for Newtonian pipe flow, few comparative studies are available. Little work has been done to develop eddy viscosity expressions for non-Newtonian and drag-reducing pipe flow. The objective of the present study is to review the expressions that have been proposed for the Newtonian case and demonstrate how these can be extended to non-Newtonian and drag-reducing flows.