A new technique for the control of a weak shock discharged from a tube

Abstract

A shock wave discharged from a tube leads to an impulsive noise that is similar to a sonic boom. The impulsive noise has often been a major factor in deterioration of the performance of flow devices and has hazardous effects on human beings. The objective of the current work is to develop a new technique for the control of the impulsive wave. Experiments using a simple shock tube were carried out to investigate the effect of a cavity/helical vane system on the magnitude of an impulsive wave. The results showed that the magnitude of the impulsive wave was influenced by the detailed configuration of the helical vane inside the cavity which was installed at the exit of a tube. The results of the tests with and without the helical vane were compared to validate the effectiveness of the present control technique. The experimental data showed that the present cavity/helical vane system reduced the peak pressure of the impulsive wave up to about 50 per cent, compared with a straight tube, and was suitable for alleviating the magnitude of the impulsive wave.