A systematic uncertainty analysis for liner impedance eduction technology

Zhou, Lin; Bodén, Hans

doi:10.1016/j.jsv.2015.07.001

Cited by 33 publications

(12 citation statements)

References 28 publications

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“…The main challenge is to ensure the best reliability of the eduction process and high accuracy of the results. 6 Recently, Roncen et al 7 dealt with a new approach based on Bayesian inference in order to have an evaluation of the uncertainties on the impedance results. For a classical perforate-overhoneycomb liner, it is usually assumed that the liner impedance is constant along the streamwise direction.…”

Section: Introductionmentioning

confidence: 99%

Liner Impedance Eduction Under Shear Grazing Flow at a High Sound Pressure Level

et al. 2020

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This paper investigates the combined effects of high sound pressure level and grazing flow on impedance eduction for classical liners. Experiments are conducted in the grazing flow duct at ONERA (B2A). The impedance is then educed with an inverse method adapted to a shear flow. To take into account the effects of incident sound pressure level, a new strategy for impedance eduction is developed, using a space-dependent variable term. The new strategy is applied to different experimental cases and the results are compared to those obtained with the classical method.

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Section: Introductionmentioning

confidence: 99%

Liner Impedance Eduction Under Shear Grazing Flow at a High Sound Pressure Level

et al. 2020

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“…However, some recent applications 7-9 have indicated a possible dependence of the educed impedance on the direction of incident waves relative to the mean flow. This unexpected behavior for locally reacting liners has led to the proposal of alternative boundary conditions and to the questioning of the hypotheses underlying the classical impedance eduction methods (see for instance Zhou and Bodén, 10 Spillere et al, 11 Bodén et al 12 ). The purpose of the current study is to investigate the effects of flow profile and axial wavenumber uncertainties on impedance eduction methods based on the Pridmore-Brown and convected Helmholtz equations for upstream and downstream sources.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Axial Wave Number and Mean Flow Uncertainty on Acoustic Liner Impedance Eduction

Nark

Jones

Piot³

2018

2018 AIAA/CEAS Aeroacoustics Conference

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“…Although most previous studies in impedance eduction focused on the minimization of a cost function [6,8], representing the mismatch between numerical and experimental fields (pressure and velocity), little effort has been dedicated to the evaluation of uncertainties in the results [14,15], associated with the measurement uncertainties inherent to the experimental observation. The method developed in the present study relies on a statistical approach to inverse problems, using Bayes's theorem.…”

Section: Bayesian Inference Applied To Liner Eductionmentioning

confidence: 99%

“…They showed the relative insensitivity of these parameters to the eduction outcome. Later, Zhou and Bodén [15] followed a modal approach, in which the flow was assumed uniform and an Ingard-Myers boundary condition was used at the liner section. The impedance was estimated from the knowledge of the axial wave number, and the uncertainty analysis was carried out on the Mach number.…”

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confidence: 99%

Statistical Inference Method for Liner Impedance Eduction with a Shear Grazing Flow

et al. 2019

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This paper presents a statistical inference method for impedance eduction in a flow-duct facility. The acoustic impedance is recast into a random variable, and Bayes's theorem is used to obtain the posterior probability density function of both its real and imaginary parts, thus expressing the knowledge/uncertainty one has on the impedance value, given a certain experimental data uncertainty. An evolutionary Markov chain Monte Carlo technique is selected to explore the probability space, and a surrogate model based on the method of snapshots is employed to speed up the calculations. The linearized Euler equations are solved using a two-dimensional discontinuous Galerkin scheme, accounting for the presence of a grazing flow. The inference process is first validated on published NASA Grazing Incidence Tube results, in which acoustic-pressure measurements on the wall opposite the liner are used as inputs. Then, the same procedure is applied to educe the impedance of a conventional single degree-of-freedom liner in the ONERA-The French Aerospace Lab B2A acoustic bench, in which a laser Doppler velocimetry (LDV) technique is used to measure the two components of the acoustic-velocity fields above the liner. The primary conclusion of the study is that the Bayesian inference method allows for consistent impedance eductions, as compared to a classical deterministic eduction approach, for both microphone and LDV measurements. Furthermore, it yields the credibility intervals of the identified impedance, which represent the uncertainty on the identified impedance values, given an uncertain measurement. The identified parameters are less correlated using an LDV-based inference than a microphone-based inference, which might be due to the more limited number of data.

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A systematic uncertainty analysis for liner impedance eduction technology

Cited by 33 publications

References 28 publications

Liner Impedance Eduction Under Shear Grazing Flow at a High Sound Pressure Level

Liner Impedance Eduction Under Shear Grazing Flow at a High Sound Pressure Level

Assessment of Axial Wave Number and Mean Flow Uncertainty on Acoustic Liner Impedance Eduction

Statistical Inference Method for Liner Impedance Eduction with a Shear Grazing Flow

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