The study of time-dependent pipe flows of inelastic non-newtonian fluids using a multiviscous approximation

Abstract

The treatment of non-linear partial differential equations of unsteady flows of non-Newtonian fluids generally leads to the use of numerical methods.The present method consists in approximating the practical shear stress/rate-of-strain curve (called here the rheogram) by a series of piecewise continuous linear segments. This method involves the solution of the linear differential equation system using a computer. The study is on unsteady laminar flows of pseudoplastic, dilatant and Bingham fluids. The results obtained by this method are compared with those determined by Laser Doppler anemometry using the Bragg cell. The results are concordant.