Evaluation of Relevance between Aerodynamic Noise Generated from Perforated Metal Plate and Velocity Fluctuation of Jet Flow

Abstract

This study deals with aerodynamic noise generated from perforated metal plate. Perforated metal plate has two flow direction and the aerodynamic noise are varied by flow direction. At the expansion direction, large prominent peak in the frequency characteristics is observed. That prominent peaks are observed in the experience by only one hole. In the experiment, velocity fluctuation of jet flow issuing from the hole is measured by a hotwire anemometer. Distribution of sound source is expected by numerical value of coherent output power (COP) calculated by velocity fluctuation and coherence function. Coherence function is defined between generated noise and velocity of jet flow. The result discovers distribution of sound sources are different by frequency of prominent peaks and interference of jet flow makes prominent peak disappeared and enlarged.