FLOW PATTERN AND FRICTIONAL LOSSES IN PULSATING PIPE FLOW - 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 flow 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 omega prime and the limits between these three regions are determined. An alternative analytical representation for wall shear stress tau // omega including acceleration term and its approximation are proposed. Various approximate representations for tau // omega reported previously or proposed here are compared with the analytical one by means of the four characteristic parameters and their applicability is examined.