Active control of transmission of turbulent boundary layer noise using smart foam elements

Griffin, J.; Johnson, Marty; Fuller, Chris R.

doi:10.1121/1.424466

Cited by 4 publications

(6 citation statements)

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“…Another important receiver position is located in the interior of the aircraft cabin, i.e., the aircraft passengers. As new aircraft designs probably exhibit new aircraft layouts (e.g., the "gamechanger" used in this paper), the cabin noise will be influenced as well [8,[39][40][41][42]. For example, in the "gamechanger" layout the engines are mounted directly to the fuselage.…”

Section: Discussionmentioning

confidence: 99%

Aircraft Noise Assessment—From Single Components to Large Scenarios

Delfs¹,

Bertsch²,

Zellmann

et al. 2018

Energies

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Abstract:The strategic European paper "Flightpath 2050" claims dramatic reductions of noise for aviation transport scenarios in 2050: ". . . The perceived noise emission of flying aircraft is reduced by 65%. These are relative to the capabilities of typical new aircraft in 2000. . . ". There is a consensus among experts that these far reaching objectives cannot be accomplished by application of noise reduction technologies at the level of aircraft components only. Comparably drastic claims simultaneously expressed in Flightpath 2050 for carbon dioxide and NOX reduction underline the need for step changes in aircraft technologies and aircraft configurations. New aircraft concepts with entirely different propulsion concepts will emerge, including unconventional power supplies from renewable energy sources, ranging from electric over hybrid to synthetic fuels. Given this foreseen revolution in aircraft technology the question arises, how the noise impact of these new aircraft may be assessed. Within the present contribution, a multi-level, multi-fidelity approach is proposed which enables aircraft noise assessment. It is composed by coupling noise prediction methods at three different levels of detail. On the first level, high fidelity methods for predicting the aeroacoustic behavior of aircraft components (and installations) are required since in the early stages of the development of innovative noise reduction technology test data is not available. The results are transferred to the second level, where radiation patterns of entire conventional and future aircraft concepts are assembled and noise emissions for single aircraft are computed. In the third level, large scale scenarios with many aircraft are considered to accurately predict the noise exposure for receivers on the ground. It is shown that reasonable predictions of the ground noise exposure level may be obtained. Furthermore, even though simplifications and omissions are introduced, it is shown that the method is capable of transferring all relevant physical aspects through the levels.

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Section: Discussionmentioning

confidence: 99%

Aircraft Noise Assessment—From Single Components to Large Scenarios

Delfs¹,

Bertsch²,

Zellmann

et al. 2018

Energies

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“…The passive component is most effective at higher frequencies, while the active component is most effective at lower frequencies. Active control is facilitated at lower frequencies because the signal processing speed demand is less which requires fewer actuators and sensors [22]. Active control techniques can ameliorate sound reduction of passive sound-absorbing materials at low frequencies [10].…”

Section: Smart Materials For Noise Vibration Reductionmentioning

confidence: 99%

“…A distinct physical characteristic of the PVDF actuator is that it is engineered to be curved in order to couple the predominantly in-plain strain associated with the piezoelectric effect and the vertical motion needed to eventually radiate sound away from the foam's surface [23]. The piezoelectric element translates an electrical input signal into a motion that radiates sound out of the surface of the smart foam element [22]. [20], [45].…”

Section: Smart Materials For Noise Vibration Reductionmentioning

confidence: 99%

“…A primary source of aircraft interior cabin noise is propeller noise and can be characterized by discrete tones at the fundamental blade passage frequency (BPF) of the engines and their subsequent harmonics [22]. In the business jet application addressed in the CREDO project, the primary noise source is the stochastic structural TBL excitation, which creates also a stochastic (diffuse) background sound field [24].…”

Section: Modeling and Measurement Of Cabin Noise Distributionmentioning

confidence: 99%

“…The DSP uses C code to determine the control parameters for the hardware configurations. The following is a methodology first suggested by Jason R. Griffin [22] which can be implemented on the controller.…”

Section: Practical Implementationmentioning

confidence: 99%

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Zone-based active noise control for an aircraft passenger seat

Ghebreiyesus¹

2021

Preprint

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The goal of this research is to improve zone-based local active noise control for an aircraft passenger seat using head tracking and virtual sensing methods. Broadband diffuse sound fields are analyzed in order to determine the level of attenuation around the passenger’s ears. The virtual sensing methods which were evaluated from literature include the virtual microphone technique, the forward difference prediction technique, and the adaptive LMS moving virtual microphone techniques. In addition to virtual sensing, a new methodology for integrating zone-based technologies with existing local ANC techniques has been developed. The virtual sensing simulation and head tracking measurements can be used to verify this methodology.

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