The Self-Noise From Ordered Structures in a Low Mach Number Jet

Abstract

This article is concerned with examining the self-noise produced by instability waves in a round jet. The self-noise is defined here as the noise attributed to the nonlinear sources in Lighthill’s stress tensor. The calculated self-noise is found to be proportional to the fourth order of the velocity amplitude saturation. The self-interaction of the instability waves results in a “super-directivity.” The dependency of the sound intensity on the Strauhal number and on the Mach number is in accordance with observations.