Host: The Japan Society of Mechanical Engineers
Name : Dynamics and Design Conference 2018
Date : August 28, 2018 - August 31, 2018
The aerodynamic noise generated by a perforated metal plate varied by air-flow direction. In the case of expansion type perforated metal, it generates very large level aerodynamic noise with a prominent peak in the frequency characteristic. In this paper, velocity fluctuation of some measuring points is measured by a hotwire anemometer to examine its cause. In the experiment, coherent output power (COP) of velocity fluctuation is calculated. The coherence function defines between generated noise and velocity fluctuation of air flow behind perforated metal plate. The expansion type perforated metal generates orderly vortex shedding and it brings the vibration of perforated metal plate. The distribution of partial overall value of COP indicates strong correlation with the plate vibration mode. That phenomenon is recognized as lock-in phenomenon between vortex and vibration of the plate.
