Preliminary investigation of impulsively blocked pipe flow

Abstract

A two-tank flow facility has been designed and tested for the study of sudden blockage in pipe flow. Preliminary experiments have been conducted to test the performance of the system. Acoustic Doppler Velocimetry was used to calibrate the flow facility and investigate the mean and fluctuating velocity components of the flow system in the absence of a blockage. Hydrogen bubble visualisation was used to visualise the velocity profile at a distance of 2 pipe diameters upstream of the pipe exit. In the absence of a blockage, a parabolic velocity profile was observed indicating fully-developed laminar pipe flow. When the flow in the pipe was suddenly blocked, the flow near the inside walls of the pipe was observed to reverse direction. Dye visualisation showed a stopping vortex near the pipe blockage. Vardi and Hwang [4], amongst others, have identified similar flow features in their studies of sudden pipe closure. The broader context of this work is to compare experimental results to the already published numerical simulations of project collaborators.