The Present and Future Role of Acoustic Metamaterials for Architectural and Urban Noise Mitigations

Owing to a steep rise in urban population, there has been a continuous growth in construction of buildings, public or private transport like cars, motorbikes, trains, and planes at a global level. Hence, urban noise has become a major issue affecting the health and quality of human life. In the current environmental scenario, architectural acoustics has been directed towards controlling and manipulating sound waves at a desired level. Structural engineers and designers are moving towards green technologies, which may help improve the overall comfort level of residents. A variety of conventional sound absorbing materials are being used to reduce noise, but attenuation of low-frequency noise still remains a challenge. Recently, acoustic metamaterials that enable low-frequency sound manipulation, mitigation, and control have been widely used for architectural acoustics and traffic noise mitigation. This review article provides an overview of the role of acoustic metamaterials for architectural acoustics and road noise mitigation applications. The current challenges and prominent future directions in the field are also highlighted.

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Plate-Type Acoustic Metamaterials: Experimental Evaluation of a Modular Large-Scale Design for Low-Frequency Noise Control

Acoustics ◽

10.3390/acoustics1020019 ◽

2019 ◽

Vol 1 (2) ◽

pp. 354-368 ◽

Cited By ~ 2

Author(s):

Linus Ang ◽

Yong Koh ◽

Heow Lee

Keyword(s):

Large Scale ◽

Noise Control ◽

Traffic Noise ◽

Low Frequency ◽

Industrial Applications ◽

Frequency Noise ◽

Acoustic Metamaterials ◽

Scale Design ◽

Stress Uniformity ◽

Plate Type

For industrial applications, the scalability of a finalised design is an important factor to consider. The scaling process of typical membrane-type acoustic metamaterials may pose manufacturing challenges such as stress uniformity of the membrane and spatial consistency of the platelet. These challenges could be addressed by plate-type acoustic metamaterials with an internal tonraum resonator. By adopting the concept of modularity in a large-scale design (or meta-panel), the acoustical performance of different specimen configurations could be scaled and modularly combined. This study justifies the viability of two meta-panel configurations for low-frequency (80–500 Hz) noise control. The meta-panels were shown to be superior to two commercially available noise barriers at 80–500 Hz. This superiority was substantiated when the sound transmission class (STC) and the outdoor-indoor transmission class (OITC) were compared. The meta-panels were also shown to provide an average noise reduction of 22.7–27.4 dB at 80–400 Hz when evaluated in different noise environments—traffic noise, aircraft flyby noise, and construction noise. Consequently, the meta-panel may be further developed and optimised to obtain a design that is lightweight and yet has good acoustical performance at below 500 Hz, which is the frequency content of most problematic noises.

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The Role of ‘Background Stressors’ in the Formation of Annoyance and Stress Responses

Journal of Low Frequency Noise Vibration and Active Control ◽

10.1177/026309239401300303 ◽

1994 ◽

Vol 13 (3) ◽

pp. 95-101 ◽

Cited By ~ 10

Author(s):

S. Benton ◽

H.G. Leventhall

Keyword(s):

Coping Strategies ◽

Stress Responses ◽

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Coping Response ◽

Chronic Effect ◽

Low Level

Background stresses have a chronic effect on our lives and stimulate the development of coping strategies. The paper considers low level low frequency noise (LLLFN) as a background stressor and the coping response to it of either improving sensitivity as an aid to location or reducing sensitivity in an attempt to habituate. It is considered that LLLFN is a proven background stressor which is not evaluated correctly by conventional noise measures.

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The Central Role of Interpersonal Conflict in Low Frequency Noise Annoyance

Noise Notes ◽

10.1260/1475-4738.6.4.3 ◽

2007 ◽

Vol 6 (4) ◽

pp. 3-18

Author(s):

Stephen Benton

Keyword(s):

Interpersonal Conflict ◽

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Noise Annoyance

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Research Progress of Locally Resonance Acoustic Metamaterials

E3S Web of Conferences ◽

10.1051/e3sconf/202124801041 ◽

2021 ◽

Vol 248 ◽

pp. 01041

Author(s):

Du Zhehua

Keyword(s):

Sound Wave ◽

Negative Refraction ◽

Low Frequency ◽

Research Progress ◽

Frequency Noise ◽

Bragg Scattering ◽

Acoustic Metamaterials ◽

Low Frequency Noise ◽

Phonon Crystal ◽

Developed Surface

Bragg scattering phonon crystal and locally resonant acoustic metamaterials were introduced. In order to generate noise reduction, the lattice constant of Bragg scattering phonon crystal should be of the same order of magnitude as the wave length of the sound wave, therefore, its application field is limited. Locally resonant acoustic metamaterials consume sound energy by coupling its own resonant frequencies with those of sound waves at close range. Its size is two orders of magnitude smaller than the wavelength of sound wave; thus, the control of low-frequency noise by small-size acoustic metamaterials is realized. Locally resonant acoustic metamaterials have some extraordinary physical characteristic in the conventional medium for their special acoustic structural units, such as negative refraction and negative mass density. Especially in low frequency band, they have acoustic forbidden band in which the sound wave transmission is prohibited. Acoustic structural unit having resonant characteristics has been developed. Surface-mounted resonant element plate structures and thin film acoustic metamaterials are the normal types of locally resonant acoustic metamaterials. Their research and development provide a new method for low-frequency noise control.

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Underwater noise mitigation in the Santa Barbara Channel through incentive-based vessel speed reduction

Scientific Reports ◽

10.1038/s41598-021-96506-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Vanessa M. ZoBell ◽

Kaitlin E. Frasier ◽

Jessica A. Morten ◽

Sean P. Hastings ◽

Lindsey E. Peavey Reeves ◽

...

Keyword(s):

Low Frequency ◽

Frequency Noise ◽

Underwater Noise ◽

Santa Barbara Channel ◽

Noise Mitigation ◽

Santa Barbara ◽

Speed Reduction ◽

Sound Exposure ◽

Exposure Levels ◽

Vessel Speed

AbstractCommercial shipping is the dominant source of low-frequency noise in the ocean. It has been shown that the noise radiated by an individual vessel depends upon the vessel’s speed. This study quantified the reduction in source levels (SLs) and sound exposure levels (SELs) for ships participating in two variations of a vessel speed reduction (VSR) program. SLs and SELs of individual ships participating in the program between 2014 and 2017 were statistically lower than non-participating ships (p < 0.001). In the 2018 fleet-based program, there were statistical differences between the SLs and SELs of fleets that participated with varying degrees of cooperation. Significant reductions in SL and SEL relied on cooperation of 25% or more in slowing vessel speed. This analysis highlights how slowing vessel speed to 10 knots or less is an effective method in reducing underwater noise emitted from commercial ships.

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Blade-Wake Interaction Noise for Turbines With Downwind Rotors

Journal of Solar Energy Engineering ◽

10.1115/1.1627830 ◽

2003 ◽

Vol 125 (4) ◽

pp. 497-505 ◽

Cited By ~ 7

Author(s):

G. M. McNerney ◽

C. P. van Dam ◽

D. T. Yen-Nakafuji

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Incidence Angle ◽

Dynamic Pressure ◽

Low Frequency ◽

Frequency Noise ◽

Atmospheric Conditions ◽

Noise Mitigation ◽

Local Flow ◽

Wake Interaction

The interaction between the rotor and the tower wake is an important source of noise for wind turbines with downwind rotors. The tower wake modifies the dynamic pressure and the local flow incidence angle as seen by the blades and, hence, modifies the aerodynamic loading of the blade during blade passage. The resulting n per revolution fluctuation in the blade loading (where n is the number of blades) is the source of low frequency but potentially high amplitude sound levels. The Wind Turbine Company (WTC) Proof of Concept 250 kW (POC) wind turbine has been observed by field personnel to produce low-frequency emissions at the National Wind Technology Center (NWTC) site during specific atmospheric conditions. Consequently, WTC is conducting a three-phase program to characterize the low frequency emissions of its two-bladed wind turbines and to develop noise mitigation techniques if needed. This paper summarizes the first phase of this program including recent low-frequency noise measurements conducted on the WTC POC250 kW wind turbine, a review of the wake characteristics of circular towers as they pertain to the blade-wake interaction problem, and techniques to attenuate the sound pressure levels caused by the blade-wake interaction.

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Semiconductor-metal interface influence on the bulk low-frequency noise behavior and role of the phonons refraction points

10.1117/12.609291 ◽

2005 ◽

Cited By ~ 2

Author(s):

H. V. Asriyan ◽

A. A. Shatveryan ◽

V. M. Aroutiounian ◽

F. V. Gasparyan ◽

S. V. Melkonyan ◽

...

Keyword(s):

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Metal Interface

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Temperature Chaos and the Lattice Character of the Hooge Parameter in Semiconductors

Modern Physics Letters B ◽

10.1142/s0217984998001475 ◽

1998 ◽

Vol 12 (29n30) ◽

pp. 1245-1254 ◽

Cited By ~ 3

Author(s):

S. V. Melkonyan ◽

F. V. Gasparyan ◽

V. M. Aroutiouyan ◽

H. V. Asriyan

Keyword(s):

Temperature Dependence ◽

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Phonon Interaction ◽

Scattering Mechanisms ◽

Electron Phonon Interaction

The influence of the electron–phonon interaction on formation of the low-frequency noise in semiconductors is theoretically considered. The determining role of scattering mechanisms in formation of the 1/f low frequency noise is shown. The temperature dependence of the Hooge parameter αH is revealed and explained. The lattice character of αH is proven.

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