Computational aero-acoustics for fan duct propagation and radiation. Current status and application to turbofan liner optimisation

Astley, R.J.; Sugimoto, Rie; Mustafi, Prateek

doi:10.1016/j.jsv.2011.03.022

Cited by 61 publications

(27 citation statements)

References 62 publications

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“…Admissibility criteria must be met for (2) to describe a passive absorbing material, 28,20 namely reality, passivity, causality, and stability. No attempt is made herein to rigorously account for these criteria, which are verified by all the models covered; two mere remarks are given.…”

Section: Generalities On Impedance Modelingmentioning

confidence: 99%

Design of broadband time-domain impedance boundary conditions using the oscillatory-diffusive representation of acoustical models

Monteghetti

Matignon

Piot

et al. 2016

The Journal of the Acoustical Society of America

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A methodology to design broadband time-domain impedance boundary conditions (TDIBCs) from the analysis of acoustical models is presented. The derived TDIBCs are recast exclusively as first-order differential equations, well-suited for high-order numerical simulations. Broadband approximations are yielded from an elementary linear least squares optimization that is, for most models, independent of the absorbing material geometry. This methodology relies on a mathematical technique referred to as the oscillatory-diffusive (or poles and cuts) representation, and is applied to a wide range of acoustical models, drawn from duct acoustics and outdoor sound propagation, which covers perforates, semi-infinite ground layers, as well as cavities filled with a porous medium. It is shown that each of these impedance models leads to a different TDIBC. Comparison with existing numerical models, such as multi-pole or extended Helmholtz resonator, provides insights into their suitability. Additionally, the broadly-applicable fractional polynomial impedance models are analyzed using fractional calculus.

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Section: Generalities On Impedance Modelingmentioning

confidence: 99%

Design of broadband time-domain impedance boundary conditions using the oscillatory-diffusive representation of acoustical models

Monteghetti

Matignon

Piot

et al. 2016

The Journal of the Acoustical Society of America

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“…For many aeroacoustic applications, the Linearized Euler Equations (LEEs) form the basic starting point for the majority of the currently used Computational AeroAcoustic (CAA) models. 12 For two decades, we have been developing the Linearised Galbrun Equation (LGE) which can be viewed as an alternative to the LEEs. However, its direct numerical treatment by Finite Element Method (FEM) has been the source of difficulties due to the well-known locking phenomenon, which usually occurs with a purely displacement based formulation.…”

Section: Numerical Model For Aeroacoustic Equationmentioning

confidence: 99%

Test of single degree of freedom acoustic treatment impedance models for multimodal acoustic propagation in duct with flow

Baccouche

Moreau

Tahar

2017

The Journal of the Acoustical Society of America

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Passive acoustic treatments, also called liners, are the main solution to noise problems. The Single Degree Of Freedom (SDOF) acoustic treatment, composed of a thin material (perforated plate) affixed to air cavities with a rigid bottom, constitutes a solution. Predicting sound level reduction by an SDOF treatment requires reliable acoustic impedance models. An experimental/numerical method has been developed for a duct with an acoustic treatment to test acoustic impedance models of SDOF treatment with a multimodal propagation in the presence of a mean flow. This method is based on the comparison of experimental results from an aeroacoustic bench composed of a circular duct with a treated area, and numerical results from an FEM-PML axisymmetric model based on Galbrun's equation. The numerical results are confronted with experimental results to test impedance models up to M=±0.25.

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“…Two optimization methods to reduce noise from turbofan aircraft engines by optimizing the acoustic treatment in engine ducts were presented by Astley et al [1].…”

Section: Introductionmentioning

confidence: 99%

“…The optimization method presented in our paper is different from those presented in [1]. Our method concerns a three parameter impedance model, namely the mass-spring-damper impedance model.…”

Section: Introductionmentioning

confidence: 99%

The Sound Attenuation Coefficient Optimization in Case of a Three Parameter Impedance Model for a Rectangular 3D Straight Lined Duct of Finite Dimensions

Bálint¹,

Bálint²,

Szabo³

et al. 2015

INCAS BULLETIN

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Computational aero-acoustics for fan duct propagation and radiation. Current status and application to turbofan liner optimisation

Cited by 61 publications

References 62 publications

Design of broadband time-domain impedance boundary conditions using the oscillatory-diffusive representation of acoustical models

Design of broadband time-domain impedance boundary conditions using the oscillatory-diffusive representation of acoustical models

Test of single degree of freedom acoustic treatment impedance models for multimodal acoustic propagation in duct with flow

The Sound Attenuation Coefficient Optimization in Case of a Three Parameter Impedance Model for a Rectangular 3D Straight Lined Duct of Finite Dimensions

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