パンチングメタル板通気時の卓越周波数騒音の発生メカニズムの解明

抄録

The purpose of this study is to elucidate the mechanism of prominent frequency noise by the air flow through a perforated metal plate. Perforated metal plate is produced by punching a sheet metal using a press die. It has two kind of direction by characteristic cross-sectional shape. The aerodynamic noise by the air flow through a perforated metal plate depends on the direction of the perforated metal plate. At the expansion direction, large prominent peak in the frequency characteristics was observed. In the experiment, the perforated metal plate was attached at a tip of circular nozzle of the wind tunnel and the aerodynamic noise and plate vibration were measured in a flow velocity 10 to 60m/s. And the natural frequency of the perforated metal plate was measured by experimental modal analysis. The measurement result show that perforated metal plate generates prominent frequency noise and perforated metal plate vibrates strongly at the same frequency. Furthermore the frequency of the prominent frequency noise matches the natural frequency of the perforated metal plate.