A New Implementation of the Extended Helmholtz Resonator Acoustic Liner Impedance Model in Time Domain CAA

Pascal, Lucas; Piot, Estelle; Casalis, Grégoire

doi:10.1142/s0218396x15500150

Cited by 9 publications

(10 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The implementation of the Extended Helmholtz Resonator proposed by Pascal et al [48] or the use of an oscillatory-diffusive representation [49] offer the possibility to keep the eigenproblem linear with respect to ω even for non-linear impedance laws. Moreover, it would be interesting for instance to take into account viscosity as it has been shown to have a significant impact on lined flow duct stability [22].…”

Section: In the Rigid Partsmentioning

confidence: 99%

Global linear stability analysis of flow in a lined duct

Pascal

Piot

Casalis

2017

Journal of Sound and Vibration

Self Cite

View full text Add to dashboard Cite

Eigenmodes of the linearised Euler equations are computed in order to study lined flow duct global stability. A simplified configuration is considered and the governing equations are discretised by means of the discontinuous Galerkin method. A biorthogonal technique is used to decompose the global eigenfunctions into local eigenmodes. The system dynamics switches from noise amplifier to resonator as the length of the liner is increased. The global mode in the liner region is shown to be mainly composed of a hydrodynamic unstable wave and a left-running acoustic mode.

show abstract

Section: In the Rigid Partsmentioning

confidence: 99%

Global linear stability analysis of flow in a lined duct

Pascal

Piot

Casalis

2017

Journal of Sound and Vibration

Self Cite

View full text Add to dashboard Cite

show abstract

“…43 Second category relates to those models that are rather built upon a mathematical modelling of the material's noise attenuation characteristics themselves, i.e., its impedance. These models [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] are of mathematical nature and do not require any prior knowledge of the material characteristics, but rather an accurate description of its noise attenuation behaviourwhich, in turns, requires a proper experimental identification (namely eduction) of its impedance spectrum. Each class of models led to the emergence of numerous TDIBC formulations, each one distinguishing itself from the others by its intrinsic modelling and/or algorithmic implementation.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, one can note the relative imbalance between the extent of efforts that was (and is still) put into developing still more innovative TDIBC models in regard to those put in assessing their practical use, whether this concerns their applicative spectrum, their numerical robustness, their ease of implementation or calibration, etc. For instance, most of TDIBC models 43,[47][48][49][50][51][52][53][56][57][58][59][60][61][62][63][64][66][67][68][69] were validated using analytical solutions that relied on simplistic conditions (e.g. no flow) and/or using rather canonical experiments.…”

Section: Introductionmentioning

confidence: 99%

Further assessment of a time domain impedance boundary condition for the numerical simulation of noise-absorbing materials

Redonnet

2021

International Journal of Aeroacoustics

View full text Add to dashboard Cite

In regard to the mitigation of environmental noise across major industry sectors, the present study focuses on the numerical prediction of passive noise reduction devices. Here, it is further explored how the noise attenuation induced by locally reacting noise absorbing materials (also called acoustic liners) can be simulated using a time domain highly accurate Computational AeroAcoustics (CAA) method. To this end, it is assessed how a classical Time Domain Impedance Boundary Condition (TDIBC) can effectively model acoustic liners of practical interest, including when the latter are exposed to realistic conditions (grazing flow and noise excitation). The investigation consists in numerically reproducing two experimental campaigns initially performed at NASA Langley Research Center. Two different materials are considered (honeycomb superimposed with perforate or wiremesh resistive face-sheet), each being characterized by a specific noise attenuation behaviour ( e.g. dependency on the flow conditions and/or noise excitation). Each material is tested under various flow conditions ( e.g. grazing flow of Mach up to 0.5) and/or noise source excitation ( e.g. multiple tones of level up to 140 dB each). The results demonstrate the ability of the underlying CAA/TDIBC approach to simulate realistic acoustic liners in non-trivial configurations, with enough physical accuracy ( e.g. correct capture of the noise attenuation characteristics) and numerical robustness ( e.g. absence of instabilities). The study also reveals that, independent from the CAA/TDIBC approach itself, some specific pre-processing tasks (e.g. impedance eduction and subsequent TDIBC calibration) may play a bigger role than expected, in practice.

show abstract

“…In [7] numerical tools to solve sound propagation in acoustic liners are reviewed, starting from the Navier-Stokes equations [5], very accurate but expensive from the computational viewpoint to some reduced formulations that even that are less accurate, they are computationally more efficient. The suppression of the diffusive term in the Navier-Stokes equations leads to the linearized Euler equations [8,9] and finally the Helmholtz equation implies the use of the hypothesis of a hometropic and irrotational flow. Finally, a check of the boundary condition can be performed.…”

Section: Introductionmentioning

confidence: 99%

Empowering Design Based on Hybrid TwinTM: Application to Acoustic Resonators

Martin

Méndez

Sainges

et al. 2020

Designs

View full text Add to dashboard Cite

In the framework of civil aviation noise levels are becoming restricted every year, on one hand to provide comfort to the passengers and on the other hand to be compliant with regulations protecting airports surroundings. New technologies are required to reduce noise to cope with this restrictions as well as to guarantee a comfortable flight for passengers. For technological industries it is compulsory to stay competitive and keep improving the technology related to air intake acoustic liners. With an unceasingly growing market, for industries it is key to stay in the vanguard of air inlet technologies, ensuring innovation and establishing a proactive environment for future product generations. One of the main objectives in this framework is the reduction of the development time of these new technologies in all the stages of the process. In this work we focus on the design stage of a new prototype and we propose a hybrid technique enabling faster design and the reduction of development time. When designing new technologies or prototypes there are usually two constraints. On one hand, more innovative prototypes may present unconventional shapes are not accurately represented by conventional physical models. On the other hand, the available data is scarce, thus limiting the use of most innovative techniques based on the state-of-art of Artificial Intelligence. In this paper we propose a solution laying in the hybrid twin paradigm, combining both, data in the low limit and physics to provide a hybrid model able to represent unconventional and innovative acoustic solutions.

show abstract

A New Implementation of the Extended Helmholtz Resonator Acoustic Liner Impedance Model in Time Domain CAA

Cited by 9 publications

References 23 publications

Global linear stability analysis of flow in a lined duct

Global linear stability analysis of flow in a lined duct

Further assessment of a time domain impedance boundary condition for the numerical simulation of noise-absorbing materials

Empowering Design Based on Hybrid TwinTM: Application to Acoustic Resonators

Contact Info

Product

Resources

About