Flow Field and Sound Radiation of a Mach 0.9 Jet Computed by LES
Abstract
Spectacular improvements in jet noise prediction have been performed in the last decade, due to the progress in numerical simulations. Noting that hybrid approaches based on acoustic analogies present difficulties related to the modelling of source terms and to the formulation of a wave operator accounting for acoustic-flow interactions, methods for computing the sound directly from the resolution of the unsteady compressible Navier-Stokes equations have been developed. The objective of this approach is to determine both the flow field and the acoustic waves in the same calculation. In this way, the computed sound field is a priori exact because no acoustic model is used. It will also permit to investigate the sound generation mechanisms since all flow and acoustic quantities are provided by the computation. However, serious numerical issues must be taken into account in this direct acoustic approach, owing to the great disparity of levels and length scales between the flow and the acoustic field. To overcome these difficulties, numerical techniques specific to Computational AeroAcoustics (CAA), suited to the behavior of acoustic waves, have been proposed, such as non dispersive and non dissipative numerical schemes, or non-reflective boundary conditions. To make direct aeroacoustic calculations, the challenge is then to combine these CAA techniques with one of the methods used to solve the Navier-Stokes equations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2003
- Accession Number
- ADP014104
Entities
People
- Christophe Bailly
- Christophe Bogey
- Daniel Juve