Validation of a Time- and Frequency-Domain Grazing Flow Acoustic Liner Model

Burak, Markus Olander; Billson, Mattias; Eriksson, Lars‐Erik; Baralon, Stephane

doi:10.2514/1.40870

Cited by 46 publications

(17 citation statements)

References 13 publications

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“…The existence of instabilities above acoustic materials in the presence of a grazing flow has been experimentally proven [3][4][5]. Sometimes, it is difficult in computations to distinguish between real and numerical instabilities [6][7][8][9][10][11]. An analysis of the different types of instability that can occur above a material is therefore of importance for a better 2 understanding of the results of experiments or computations.…”

Section: Introductionmentioning

confidence: 99%

Slow sound laser in lined flow ducts

Coutant

Aurégan

Pagneux

2019

The Journal of the Acoustical Society of America

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This work considers the propagation of sound in a waveguide with an impedance wall. In the low frequency regime, the first effect of the impedance is to decrease the propagation speed of acoustic waves. Therefore, a flow in the duct can exceed the wave propagation speed at low Mach numbers, making it effectively supersonic. This work analyzes a setup where the impedance along the wall varies such that the duct is supersonic then subsonic in a finite region and supersonic again. In this specific configuration, the subsonic region act as a resonant cavity, and triggers a laser-like instability. This work shows that the instability is highly subwavelength. Besides, if the subsonic region is small enough, the instability is static. This worl also analyzes the effect of a shear flow layer near the impedance wall. Although its presence significantly alter the instability, its main properties are maintained. This work points out the analogy between the present instability and a similar one in fluid analogues of black holes known as the black hole laser.

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Section: Introductionmentioning

confidence: 99%

Slow sound laser in lined flow ducts

Coutant

Aurégan

Pagneux

2019

The Journal of the Acoustical Society of America

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“…This instability has been reported previously in Refs. [26,14]. As it is not included in the present methodology, the disagreement with the data here is to be expected.…”

Section: Differences Between the Experimental And Numerical Valuesmentioning

confidence: 41%

“…Despite the limitations of the Myers boundary condition, the methodology has captured the reduction in SPL across the liner using impedance values which are consistent with those educed using more computationally demanding procedures in Refs. [11,26,14].…”

Section: Discussionmentioning

confidence: 99%

“…[11], was collected specifically for the purpose of validating acoustic propagation codes and is the most comprehensive available. As such, it has been widely used to benchmark the use of flow impedance boundary conditions in numerical schemes [12,26,14,13].…”

Section: Validation Of the Propagation Methodologymentioning

confidence: 99%

“…The results are compared against the data from the grazing incidence tube (GIT) at the NASA Langley Research Center, published by Jones et al [11] in Section 5. These data are the most extensive available for such a configuration and have been widely used to benchmark the use of flow impedance boundary conditions in numerical schemes [12,13,14]. These results are discussed further along with the improved efficiency of the methodology in Section 6, before conclusion are presented in Section 7.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A wave expansion method for acoustic propagation in lined flow ducts

O’Reilly

2015

Applied Acoustics

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Acoustic liners are used extensively in engineering applications, particularly in aero-engines and automotive exhaust systems. In this paper, a flow impedance boundary conditions is introduced into the wave expansion method with the aim of providing an efficient methodology for computing the acoustic propagation through a lined duct with flow. For a potential flow, the boundary layer and the lined wall are included in the discretisation scheme by the Myers flow impedance boundary condition. The acoustic propagation through a flow-impedance tube is computed in order to validate the implementation of the impedance boundary condition in this scheme. The results show that this computationally light methodology provides generally good agreement with the experimental data.

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Passive control of combustion instabilities

Zhao¹

2023

Thermoacoustic Combustion Instability Control

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Validation of a Time- and Frequency-Domain Grazing Flow Acoustic Liner Model

Cited by 46 publications

References 13 publications

Slow sound laser in lined flow ducts

Slow sound laser in lined flow ducts

A wave expansion method for acoustic propagation in lined flow ducts

Passive control of combustion instabilities

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