Numerical study on acoustic intensity of edge tone with change of jet velocity

Abstract

To understand the sounding mechanism of “air-jet” instruments we numerically study the acoustic intensity of edge tone, i.e., the sound source of “air-jet” instruments, with compressible LES and DNS comparing with experimental results. The edge tone is aerodynamic sound and we need to investigate the sound generation based on Lighthill’s theory. According to Lighthill’s theory, the acoustic intensity increases the eighth power of fluid velocity in transonic and subsonic ranges, but it may obey different rules in a range less than the subsonic. Indeed, we find with compressible LES that the edge tone has three stages, in each of which a different increasing rate is observed. In particular, the fundamental and second modes obey the second-power law in the second stage. The same result was obtained by an experiment provided by YAMAHA Corporation. To clarify the radiation mechanism of the edge tone, which exhibits the three stage, we have to calculate Lighthill’s sound source with high accuracy. So, we will s...