Computation of Acoustic Far‐Fields with the Spectral Lighthill Method

Abstract

Based on Lighthill's acoustic analogy we formulate the Spectral Lighthill Method (SLM). SLM is a method for the computation of acoustic far‐fields. It uses a spatio‐temporal Fourier transform of the Lighthill stress tensor. We show that SLM is a straightforward tool for the computation of acoustic far‐fields that enhances our physical understanding of sound generation and is useful in the numerical analysis of acoustic far‐field solvers. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

An Euler solver for the acoustic far‐field prediction of compressible jet flow

“…Therefore, numerical tools that are of help in early design stages of future jet engines will most likely rely on a hybrid approach -the coupling of a simulation which determines the time-dependent flow with a solver that then propagates the sound waves to distant observer positions. In previous work we developed a simulation environment for high Reynolds number, high-subsonic round jet flow [1,2] and set forth a reformulation [3] of the acoustic analogy of Lighthill [4]. Based thereon the motivation for the development of an Euler solver is twofold: First, we would like to efficiently and accurately predict jet noise not only in the acoustic near-field but also in the far-field region which is subject of most experimental investigations, as well as of interest to most practical applications.…”

“…Based thereon the motivation for the development of an Euler solver is twofold: First, we would like to efficiently and accurately predict jet noise not only in the acoustic near-field but also in the far-field region which is subject of most experimental investigations, as well as of interest to most practical applications. Second, we want to investigate the operative range of a previously developed analytical acoustic far-field solver, the SLM (Spectral Lighthill method) [3]. In this contribution, details of the computational scheme of the Euler solver will be presented.…”