Abstract
This paper deals with the aerodynamic sound generated by the perforated metal. Perforated metal is produced by stamp out the sheet metal using a press die. In this study, the perforated metal is attached at the tip of circular nozzle and it experiments by wind velocity 50 m/s. Aerodynamic sound measurement experiments show that the characteristics of the generated aerodynamic sound depend on the perforated metal thickness, hole diameter and its attachment orientation. Moreover, the measurement of velocity fluctuation of air flow flowing out from perforated metal is carried out. The result shows the perforated metal is effectivity for reduce the low frequency noise. The distribution of band overall of velocity fluctuation indicates the mechanism of reducing the low frequency noise generate from the jet.
