Experimental Evaluation of Acoustic Engine Liner Models Developed with COMSOL Multiphysics

Schiller, Noah H.; Jones, Michael G.; Bertolucci, Brandon

doi:10.2514/6.2017-4186

Cited by 10 publications

(6 citation statements)

References 7 publications

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“…Schiller et al. 7 evaluated COMSOL Multiphysics, a commercially available finite element software, for modeling acoustic liners in a grazing flow setup. The authors studied so called “reaction liners” which incorporate back cavity volume without lateral partitions as opposed to traditional liners with honeycomb cells.…”

Section: Literature Reviewmentioning

confidence: 99%

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High fidelity modeling tools for engine liner design and screening of advanced concepts

Winkler

Mendoza

Reimann

et al. 2021

International Journal of Aeroacoustics

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With aircraft engines trending toward ultra-high bypass ratios, resulting in lower fan pressure ratios, lower fan RPM, and therefore lower blade pass frequency, the aircraft engine liner design space has been dramatically altered. This result is also due to the associated reduction in both the available acoustic treatment area (axial extent) as well as thickness (liner depth). As a consequence, there is current need for novel acoustic liner technologies that are able to meet multiple physical constraints and simultaneously provide enhanced noise attenuation capabilities. In addition, recent advances in additive manufacturing have enabled the consideration of complex liner backing structures that would traditionally be limited to honeycomb cores. This paper provides an overview of engine liner modeling and a description of the key physical mechanisms, with some emphasis on the use of low to high-fidelity tools such as empirical models and commercially available software such as COMSOL, Actran, and PowerFLOW. It is shown that the higher fidelity tools are a critical enabler for the evaluation and construction of future complex liner structures. A systematic study is conducted to predict the acoustic performance of traditional single degree of freedom liners and comparisons are made to experimental data. The effects of grazing flow and bias flow are briefly addressed. Finally, a more advanced structure, a metamaterial, is modeled and the acoustic performance is discussed.

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Section: Literature Reviewmentioning

confidence: 99%

“…This approach is therefore similar to the approach used by Schiller at al. 7 and Sugimoto et al. 10 as described in the literature review section.…”

Section: Advanced Liner Concept Evaluationmentioning

confidence: 99%

High fidelity modeling tools for engine liner design and screening of advanced concepts

Winkler

Mendoza

Reimann

et al. 2021

International Journal of Aeroacoustics

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“…Specifically, is assumed to equal 320 and is set to 1.16 as described in Ref. [12]. In contrast, the standard empirical coefficients are used to predict the transfer impedance of the facesheet with grazing flow.…”

Section: Facesheet Transfer Impedancementioning

confidence: 99%

“…The search is complete when the average relative change in the objective function, defined in Eq. (12), is less than 10 −6 over 500 consecutive generations, with a population size of 90. While there is significant variability between runs, an average run converges in approximately 700 generations and requires 63k function evaluations.…”

Section: B Design 2: Nit Broadband Designmentioning

confidence: 99%

Initial Developments of a Low-Drag, Variable-Depth Acoustic Liner

Schiller

Jones

Howerton

et al. 2019

25th AIAA/CEAS Aeroacoustics Conference

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The purpose of this study is to assess the acoustic performance and relative drag of a new type of variable depth liner containing pairs of resonators coupled together by shared inlet volumes just below the facesheet. This type of liner has the potential to achieve a targeted impedance with fewer openings in the facesheet, and therefore less drag, than previous designs. To better understand the limitations of the concept, three sets of samples were designed and tested in the NASA Langley normal incidence and grazing flow impedance tubes. Each set of samples consisted of a baseline variable depth liner with straight chambers, and a prototype liner with shared inlet volumes. Measurements conducted in both the normal incidence and grazing flow impedance tubes confirm that the prototype liner can achieve the same impedance as the baseline variable depth liner at discrete frequencies with 50% less open area. This results in a 75% reduction in the drag penalty relative to the baseline design. The proposed concept is not, however, able to achieve a flat, broadband impedance as effectively as the baseline liner. So, while the proposed concept is well suited for multitonal design metrics, tradeoffs must be made between liner drag and acoustic performance when broadband attenuation is required.

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“…For passive noise reduction of a duct, it is general to apply acoustic treatments to the wall of the duct. Typically, a variety of liners, such as perforate-over-honeycomb core liners and metal foam (Lu et al, 2016; Schiller et al, 2017; Yang and Cheng, 2016), can be buried in the inner side of the engine nacelle to achieve sound attenuation. The perforate-over-honeycomb core liner, which effectively reduces tonal noise and is widely studied (Spillere et al, 2020; Yang et al, 2018; Zhang et al, 2021), is a typical locally reacting liner.…”

Section: Introductionmentioning

confidence: 99%

An investigation on the modelling of a finite porous liner for the sound propagation in a rectangular duct

Song

Yuan

et al. 2022

Journal of Vibration and Control

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Acoustic liners take an essential role in the noise attenuation in ducts. In this work, the multimodal method based on the finite-difference method is extended to predict the acoustic field in a rectangular duct lined with a finite porous material and validated by the experiment. A modified immersed interface method is developed for the air–porous interface problem in the extended multimodal method without flow. When the flow exists, the treatments of the air–porous interface problem and the continuity of pressure between the wall and liner are also given. Three ways of describing the porous liner using the surface impedance at normal incidence named normal impedance, the surface impedance at grazing incidence named shear impedance and a cavity filled with the equivalent fluid of porous material are introduced. The comparison among the three ways reveals that the extended method of treating liners using a cavity filled with the equivalent fluid is more accurate for the acoustic evaluation of porous liners. The analysis finds that the shear impedance can reasonably present the influence of porous material during the comparisons of transmission loss curves of the liners with different lengths and depths at different Mach numbers. In most cases, the prediction by the shear impedance is closer to that simulated by the cavity filled with porous material than the normal impedance. Normal impedance is hardly utilized to describe the porous material and is only reliable when the cavity is very short and deep.

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Experimental Evaluation of Acoustic Engine Liner Models Developed with COMSOL Multiphysics

Cited by 10 publications

References 7 publications

High fidelity modeling tools for engine liner design and screening of advanced concepts

High fidelity modeling tools for engine liner design and screening of advanced concepts

Initial Developments of a Low-Drag, Variable-Depth Acoustic Liner

An investigation on the modelling of a finite porous liner for the sound propagation in a rectangular duct

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