Experimental Investigation on Circular Cylinders with Metal Foam for Noise Reduction

摘要

Covering the circular cylinder with metal foam is one of the effective methods to reduce aerodynamic noises. In order to investigate the mechanism of noise reduction of porous metal, acoustic and velocity measurements were conducted in an aeroacoustic wind tunnel using microphone and constant temperature anemometry, respectively. The results show that the tonal noise produced by the cylinder covered with the metal foam is reduced significantly. By further analysis of the velocity field of the cylinder wake, it shows that metal foam decreases the frequency of the vortex shedding and reduces the velocity in the wake. In addition, the width of the wake region is broadened for cylinder covered with metal foam.