A Conventional Liner Acoustic/Drag Interaction Benchmark Database

Howerton, Brian M.; Jones, Michael G.

doi:10.2514/6.2017-4190

Cited by 14 publications

(7 citation statements)

References 6 publications

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“…Some of these studies focused on developing measurement approaches to determine the effects of an acoustic pressure field on the drag due to the acoustic liner. [22,[35][36][37] Others sought to find ways to reduce the drag, whether by reducing the porosity or by altering the shape of the facesheet perforations.…”

Section: B Single and Two Degree-of-freedom Linersmentioning

confidence: 99%

Broadband and Low-Frequency Acoustic Liner Investigations at NASA and ONERA

2022

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Section: B Single and Two Degree-of-freedom Linersmentioning

confidence: 99%

Broadband and Low-Frequency Acoustic Liner Investigations at NASA and ONERA

2022

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“…Static pressure measurements were acquired at the same flow speed, but with the acoustic drivers off. While the acoustic component of liner drag can be important at high sound pressure levels (e.g., around 150 dB), the low levels used in this test were expected to have no appreciable impact on liner drag [3]. The liner resistance factor was calculated based on the static pressure drop measurements as described in Ref.…”

Section: Fig 5 Sketch Of the Nasa Langley Grazing Flow Impedance Tube (Gfit) Measurement Sectionmentioning

confidence: 99%

“…An experimental study conducted by Ref. [3] identified a strong relationship between the liner drag and the open area ratio of the facesheet. As the open area is reduced, the drag decreases, approaching the drag of a smooth wall as the open area goes to zero.…”

Section: Introductionmentioning

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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“…The coupling between aerodynamic and acoustic effects is complex, as liners increase the viscous drag in the turbulent layer compared to a smooth surface. Howerton et al [12] investigated the drag effect of several conventional or more advanced liner designs in the NASA GFIT. They found that the resistance factor (also known as the friction factor) was frequency-dependent in presence of acoustic excitation.…”

Section: Introductionmentioning

confidence: 99%