Augmentation of the magnitude of the impulsive wave discharging from a tube

Abstract

The present paper describes experimental and computational work to augment the magnitude of the impulsive wave generated at the exit of a pipe. An experiment was performed using a simple shock tube with an open end, and numerical calculations were carried out to solve the unsteady, axisymmetric, inviscid, compressible governing equations that represent the experimental flowfield. The control strategy applied was to alter the exit geometry of a straight tube to a sudden enlargement tube and a flare tube. The effects of the configurations of the tube exit on the magnitude of the impulsive wave were investigated over the range of weak shock Mach numbers from 1.01 to 1.10. Various types of geometric parameter were explored for the configurations of the tube exit. The results obtained were compared with those of the straight tube tests. The numerical result predicted the magnitude of the experimented impulsive waves with a good accuracy. The present passive control technique enabled the magnitude of the impulsive wave to be augmented by about 24 per cent, compared with that of the straight tube with no control.