Stochastic Sources of Broadband Noise for Time-Domain Simulations of Duct Acoustics

Abstract

Broadband fan noise is comprised of a wide range of frequencies and at each frequency the acoustic energy is distributed over all the cut-on modes. Simulating the propagation and absorption of broadband noise is further complicated by the random nature of the sound field. This paper presents a computational method to generate truly broadband multi-mode noise in a time-domain simulation. This is achieved by defining a stochastic source that is tailored to radiate a sound field characterized by the cross-correlation between modal amplitudes. This stochastic source allows to compute in a single time-domain simulation the complete spectrum of the broadband multi-mode sound field. Unlike other methods proposed for generating broadband noise, there is no need to perform several simulations for different realizations.