Pulsating Flow in a Curved Pipe (Secondary Flow)

Abstract

The secondary flow pattern was clarified experimentally by the visualization method for a fully developed pulsating flow through a circular curved pipe with a curvature ratio of 7.6. The experiments were carried out under the conditions of the Womersley numbers of α=5.5～18, the mean Dean numbers of D^^-=90 and 200, and the flow rate ratios of η=0.5 and/or 1. Photographs were taken at four selected phase positions, i.e. Θ=0゜, 90゜, 180゜ and 270゜. The instantaneous velocity profiles, the center of the vortices and the kinetic energy of the secondary flow were determined with the aid of the photographs and compared with the results obtained by the numerical analysis .For the experimental and analytical results, a discussion is given for the transition of the secondary flow patterns in a period and the effects of the Womersley number on the flow behavior.