On the effect of Mach number and coflow for turbulent jet noise sources

Abstract

A modern acoustic analogy method based on the Goldstein formulation is used for modelling the acoustic properties of several low Reynolds number jets from a DNS database. The key feature of this work is accounting for the well-developed turbulent boundary layer effects and the influence of the coflow. Fourth-order correlation analysis is applied for 3 jet cases of different inflow velocities and coflow speeds. The results for different jet cases are compared and contrasted from the viewpoint of the effect of coflow on jet noise. For two of the jet cases that correspond to the most converged DNS near-field data, far-field acoustic predictions are obtained and compared with the reference far-f..