Flow Pattern and Frictional Losses in Pulsating Pipe Flow : Part 5, Wall Shear Stress and Flow Pattern in a Laminar Flow

Abstract

By introducing four characteristic parameters defined for a pulsating turbulent pipe flow, the pattern diagrams for a pulsating laminar pipe flow are shown. The flow patterns are classified into three types, i. e., quasi-steady, intermediate, and inertia dominant ones with respect to the dimensionless frequency ω' and the limits between these three regions are determined. An alternative analytical representation for wall shear stress τ_w including acceleration term and its approximation are proposed. Various approximate representations for τ_w reported previously or proposed here are compared with the analytical one by means of the four characteristic parameters and their applicability is examined.