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

The present paper describes experimental and computational work to augment the magnitude of the impulsive wave generated at the exit of a pipe. An exp eriment was performed using a simple shock tube with an open end, and numer ical calculations were carried out to solve the unsteady, axisymmetric, inv iscid, compressible governing equations that represent the experimental flo wfield. The control strategy applied was to alter the exit geometry of a st raight tube to a sudden enlargement tube and a flare tube. The effects of t he configurations of the tube exit on the magnitude of the impulsive wave w ere investigated over the range of weak shock Mach numbers from 1.01 to 1.1 0. Various types of geometric parameter were explored for the configuration s of the tube exit. The results obtained were compared with those of the st raight tube tests. The numerical result predicted the magnitude of the expe rimented impulsive waves with a good accuracy. The present passive control technique enabled the magnitude of the impulsive wave to be augmented by ab out 24 per cent, compared with that of the straight tube with no control.