打ち抜き加工された小孔から発生する空力騒音

抄録

Aerodynamic noise is a problem in an exhaust system of large size diesel engine in factories. Because of high-speed exhaust gas, the low frequency aerodynamic noise generates in the silencer. Precisely, aerodynamic noise is related to the formation of vortex. Therefore, we focus on perforated metal which is effective to reduce the scale of vortex. Perforated metal is produced by punching the sheet metal using a press die. It has two kind of direction by its cross-sectional shape. One is “Expansion” the other is “Shrinkage”. In this paper, we measure the aerodynamic noise generated by the airflow through punched small holes. Experimental condition change number of holes, direction of the plate and thickness of it. As a result cross-sectional shape has effect on vortex formation and interference of vortex. When the thickness is increase, it is the effective cross-sectional shape for aerodynamic noise.