Experimental Study on Passive Control of Pseudo-Shock

Abstract

It is well known that the pseudo-shock in the straight duct oscillates severely, and causes vibration and noise of fluid machines. In the previous paper, the performance of the diffuser is shown to be improved by the passive control method without noticeable changes of the pseudo-shock stracture, and a new passive control method of the pseudo-shock useing the bypass system was proposed. In the present paper, the effectiveness of these methods for the oscillation suppression of the pseudo-shock was investigated exprimentally. Both of these methods can suppress the wall pressure fluctuation, reducing the pressure gradient and the shock oscillation amplitude.