Bias flow adaptive acoustic liner

Kwan, H. W.; Yu, Jia; Beer, B.; Armitage, David

doi:10.2514/6.1999-1939

Cited by 4 publications

(2 citation statements)

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“…Bias flow is most relevant in combustion applications where cooling flow through the liner facesheet is required or needed based on material constraints. However, the addition of bias flow has also been studied as a means to control the impedance in nacelle liners during different flight conditions 33,34 and is therefore relevant to advanced nacelle liner concepts. To study the effect of bias flow through the facesheet of the SDOF liner using the high-fidelity LBM approach, the same grazing flow facility numerical setup (Figure 12) is used.…”

Section: High-fidelity Liner Simulationsmentioning

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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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: High-fidelity Liner Simulationsmentioning

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

View full text Add to dashboard Cite

show abstract

“…In the situation of zero grazing #ow and normally incident sound, the work of Hughes and Dowling [4], and Zhao and Sun [5] makes evident the high performance of the tunable acoustic liner with bias #ow. Recently, more realistic experiments in which this type of tunable acoustic liner is used in a #ow duct were carried out by Kwan et al [6], and Cataldi et al [7]. In reference [7], bias #ow into or out of a liner (in#ow or out#ow) is used for controlling the liner impedance with grazing #ow being present.…”

Section: Introductionmentioning

confidence: 99%