Passive control of an impulsive wave using a cavity/helical vane system

Abstract

In many engineering practices, frequently an impulsive wave is a consequence of discharge of a shock wave from the exit of a tube, leading to an annoying noise like a sonic boom. The impulsive noise has often been a major factor to limit the performance of flow devices as well as to affect hazardous influences on human being. The current paper describes a new control method for the reduction of impulsive wave. An experiment using a simple shock tube was carried out to examine the effect of a cavity/helical vane system on the impulsive wave strength. The resulting impulsive wave was influenced by the detailed configuration of the helical vane inside the cavity which is located at the vicinity of the exit of a tube. The effect of the helical vane was compared with no helical vane tests to ensure validation of this kind of control strategy. The results showed that the strength of the impulsive wave could be significantly reduced by the current passive control using the cavity/helical vane system.