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Journal articles on the topic 'Mitigation acoustic noise reduction'
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1
Sahu, Ashish Kumar, Abeka Selliah, Alaa Hassan, Moien Masoumi, and Berker Bilgin. "Experimental Evaluation of Acoustical Materials for Noise Reduction in an Induction Motor Drive." Machines 12, no. 8 (2024): 499. http://dx.doi.org/10.3390/machines12080499.
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Electric propulsion motors are more efficient than internal combustion engines, but they generate high-frequency tonal noise, which can be perceived as annoying. Acoustical materials are typically suitable for high-frequency noise, making them ideal for acoustic noise mitigation. This paper investigates the effectiveness of three acoustical materials, namely, 2″ Polyurethane foam, 2″ Vinyl-faced quilted glass fiber, and 2″ Studiofoam, in mitigating the acoustic noise from an induction motor and a variable frequency inverter. Acoustic noise rates at multiple motor speeds, with and without the application of acoustical materials, are compared to determine the effectiveness of acoustical materials in mitigating acoustic noise at the transmission stage. Acoustical materials reduce acoustic noise from the induction motor by 5–14 dB(A) at around 500 Hz and by 22–31 dB(A) at around 10,000 Hz. Among the tested materials, Studiofoam demonstrates superior noise absorption capacity across the entire frequency range. Polyurethane foam is a cost-effective and lightweight alternative, and it is equally as effective as Studifoam in mitigating high-frequency acoustic noise above 5000 Hz.
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Azimi, Mariam, and Mohammadreza Azimi. "Noise Mitigation in Buildings Using Sound Absorbing Materials." NOISE THEORY AND PRACTICE 1, no. 1 (2015): 12–16. https://doi.org/10.5281/zenodo.1469408.
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Noise, generally defined as undesirable sound, is characterized in terms of the pressure of the sound wave. The improvement on the human quality of life and the continuous growth in population in developing and developed societies, have exacerbated the environmental and financial issues. Some of these problems are noise and the different types of human an industrial wastes. Many natural products have been recently developed and tested for acoustic applications. Sound-absorbing materials absorb most of the sound energy striking them and reflect very little. Therefore, sound-absorbing materials have been found to be very useful for the control of room noise. In this study, sound absorption technology as an effective noise reduction technology buildings using sustainable acoustic absorbers, will be discussed.
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Yun-Ke, Luo, Song Li-Zhong, Zhang Chao, and Ni Yi-Qing. "Experimental evaluation and numerical interpretation of various noise mitigation strategies for in-service elevated suburban rail." Measurement 219, no. 2023 (2023): 113276. https://doi.org/10.1016/j.measurement.2023.113276.
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This research evaluates the efficiency of five noise mitigation measures including rubber floating slab track, straight noise barrier, track acoustic absorber, track-side noise barrier, semi-closed noise barrier, and a combined strategy on an elevated railway through in-situ measurements. In-situ experiments were conducted by sequen- tially installing various mitigation measures for comparative evaluation. A numerical model was then developed to interpret the noise control characteristics of the mitigation measures. The experimental results indicate that the rubber floating slab track can mitigate bridge-borne noise by 0-4 dB sound pressure level (SPL); the track acoustic absorber can mitigate the railway noise by 3–5 dB(A) and its combination with track-side noise barrier boosts the insertion losses of SPL by 2–7 dB(A). The combined control strategy shows overall better performance than individual mitigation measures within the efficient noise reduction regions. The experimental and nu- merical results can serve as a guide on the design of noise control strategies for elevated railways.
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Jarnut, Marcin, Jacek Kaniewski, and Mariusz Buciakowski. "Review on Noise Generation Issues and Noise Mitigation Methods in Electric Vehicle Charging Systems." Energies 18, no. 4 (2025): 778. https://doi.org/10.3390/en18040778.
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This paper presents an overview of issues related to noise generation in electric vehicle (EV) charging systems. It discusses the requirements for noise reduction in locations where charging stations are most commonly installed. The primary sources of noise in EV charging stations are identified, considering their design and configuration. The results of acoustic tests for specific noise sources and entire charging stations are presented, including measurements of sound pressure level (SPL), acoustic imaging, and the generated acoustic spectrum. The paper also describes noise reduction methods and proposes solutions aimed at minimizing the noise generated by charging infrastructure. Additionally, the results of tests illustrating the effectiveness of these methods are presented.
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Xiong, Zixiang, Xuxu Zhuang, Zhaoyong Sun, and Liuxian Zhao. "Coupled Helmholtz resonators for broadband Aeroacoustic noise mitigation." Sound & Vibration 59, no. 1 (2024): 1702. https://doi.org/10.59400/sv1702.
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As a structurally simple acoustic element, Helmholtz resonators can exhibit strong resonance when acoustic waves enter the cavity, thus providing excellent sound absorption effects. Consequently, they are widely applied in automotive engine and exhaust systems. This paper systematically investigates the noise reduction performance of multiple coupled Helmholtz resonators under conditions with and without tangential flow. A finite element simulation model with multiple Helmholtz resonators is established by employing COMSOL Multiphysics software to solve the linearized Navier-Stokes equations in the frequency domain. The simulation results demonstrate that the structure, which couples multiple Helmholtz resonators, can effectively broaden the low-frequency sound absorption band under the influence of a flow field, enhancing the transmission loss across the entire low-frequency band. This structure holds significant potential for applications in automotive exhaust systems and aero-engine noise reduction.
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SOUSA, Laura, Luís GODINHO, and Paulo AMADO MENDES. "Enhancing railway noise reduction through advanced multilayer acoustic absorbent systems with tunable resonators." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 2 (2024): 9027–37. http://dx.doi.org/10.3397/in_2024_4174.
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Railway noise poses a significant environmental challenge, prompting the need for effective mitigation strategies. In response, noise barriers are often employed to reduce noise near railways. This research focuses on the use of porous materials, more specifically porous concrete, for acoustic absorption, particularly in the context of railway noise reduction. A novel approach is proposed, wherein porous multilayer metamaterial systems are developed, with each layer's macroscopic parameters strategically optimized to enhance the overall sound absorption curve. Additionally, to broaden the frequency range of noise attenuation, tunable resonators are seamlessly integrated into the multilayer system. The analytical framework for analyzing both the multilayer system and resonators involves employing equivalent fluid models and the analytical transfer matrix method. Linear regressions were employed to establish relationships between porosity, density, and other macroscopic parameters, enabling the derivation of the sound absorption curve solely from these parameters. Through systematic optimization and integration of resonators, it is expected that, the proposed approach demonstrates significant advancements in railway noise reduction efficacy across a wide frequency range. This research aims to contribute to the development of more efficient and versatile acoustic absorbent systems for mitigating railway noise pollution.
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Fusaro, Gioia, Xiang Yu, Zhenbo Lu, Fangsen Cui, and Jian Kang. "A Metawindow with Optimised Acoustic and Ventilation Performance." Applied Sciences 11, no. 7 (2021): 3168. http://dx.doi.org/10.3390/app11073168.
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Crucial factors in window performance, such as natural ventilation and noise control, are generally conceived separately, forcing users to choose one over the other. To solve this dualism, this study aimed to develop an acoustic metamaterial (AMM) ergonomic window design to allow noise control without dependence on the natural ventilation duration and vice versa. First, the finite element method (FEM) was used to investigate the noise control performance of the acoustic metawindow (AMW) unit, followed by anechoic chamber testing, which also served as the validation of the FEM models. Furthermore, FEM analysis was used to optimise the acoustic performance and assess the ventilation potential. The numerical and experimental results exhibited an overall mean sound reduction of 15 dB within a bandwidth of 380 to 5000 Hz. A good agreement between the measured and numerical results was obtained, with a mean variation of 30%. Therefore, the AMW unit optimised acoustic performance, resulting in a higher noise reduction, especially from 50 to 500 Hz. Finally, most of the AMW unit configurations are suitable for natural ventilation, and a dynamic tuned ventilation capacity can be achieved for particular ranges by adjusting the window’s ventilation opening. The proposed designs have potential applications in building acoustics and engineering where natural ventilation and noise mitigation are required to meet regulations simultaneously.
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Li, Jinyu, Gang Cao, Shujiao Chen, Xiaoyan Lei, and Zhongqiu Zuo. "Study on superposition sound field of filter devices used in power converter stations." Journal of Physics: Conference Series 3031, no. 1 (2025): 012010. https://doi.org/10.1088/1742-6596/3031/1/012010.
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Abstract High-Voltage Direct-Current (HVDC) transmission systems provide a critical means of delivering clean energy to economically developed areas. However, noise pollution from converter stations, particularly from filter devices such as capacitors and reactors, has become a significant concern. This paper investigates the acoustic noise generated by these filter devices, focusing on the superposition of sound fields produced by capacitors and reactors. The theoretical analysis of sound pressure superposition reveals the influence of phase differences between the sound waves emitted by each device, and experimental measurements validate these findings. By analysing sound field distributions under various excitation conditions, this paper demonstrates that interference effects between reactor and capacitor noise are prominent, significantly affecting the total noise level. The results highlight the importance of understanding the interactions between these sound sources for effective noise reduction in HVDC converter stations. This paper provides valuable insights for optimizing acoustic management strategies in power converter stations, contributing to both noise mitigation and improved environmental acoustics.
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Brick, Haike, and Jenny Böhm. "Field-testing of noise abatement measures." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 7 (2023): 830–37. http://dx.doi.org/10.3397/in_2022_0117.
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The strengthening of rail transport must be accompanied by a reduction in emissions. Regarding acoustics, innovative measures to increase noise protection must therefore be developed and investigated. Nevertheless, the determination of the sound reduction effect of mitigation measures on the railway infrastructure or in the propagation path is not yet standardised. There is a need for the development of a measurement and evaluation procedure, which is practice-oriented, reliable and allows the assessment of innovative measures in approval procedures. The German Centre for Rail Traffic Research (DZSF) at the Federal Railway Authority - an independent, scientific research facility of the German Federal Government - will support these activities. In addition to theoretical investigations, the Open Digital Test Field, which is being set up by the DZSF in the Lusatia region between Halle (Saale) - Cottbus - Niesky, is available for practical tests. Before starting the field tests, measurement procedure and boundary conditions are to be defined. The requirements and methods for quantifying mitigation measures formulated in previous research projects are outlined and reviewed. The presentation will discuss a derived proposal and show the selection of acoustic test sections in the Open Digital Test Field that meet the requirements.
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Ahmed, Shakeel, Muhammad Tahir Akhtar, and Xi Zhang. "Online acoustic feedback mitigation with improved noise‐reduction performance in active noise control systems." IET Signal Processing 7, no. 6 (2013): 505–14. http://dx.doi.org/10.1049/iet-spr.2012.0204.
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Xu, Yiquan, and Yiquan Xu. "FDTD-Based Simulation and Analysis of Noise Reduction Effects in Hospital Wards." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 2 (2023): 5884–92. http://dx.doi.org/10.3397/in_2022_0873.
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The impact of domestic hospital acoustic environment on the health of patients and healthcare workers is attracting more and more attention. This paper investigated and analyzed the noise situation of typical double wards in hospital, and designed noise reduction schemes according to its noise sources; based on finite difference time domain method (FDTD), sound fields in wards were simulated before and after noise reduction treatments, and noise reduction results were compared and analyzed. Results show that FDTD can be used to effectively model sound field of wards with complex boundary conditions; meanwhile, the noise mitigation processes have significant effects on improvement of reverberation time and speech intelligibility in wards.
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Challa, Ganesh, and Dr M. Damodar Reddy. "Acoustic Noise Mitigation in Slip Angle Controlled DTC of Open-End Winding Induction Motor Drive Using Dual Randomized AISPWM for EV Application." International Journal of Electrical and Electronics Research 12, ETEVS (2024): 19–24. http://dx.doi.org/10.37391/ijeer.12et-evs04.
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Low vibration and acoustical noise as well as effective DC link usage are the demands of industries and Electric Vehicles (EV). Direct Torque Control (DTC) of Induction Motors (IMs) meet the EV and other modern industry requirements. Still, flux as well as torque swings lead to higher acoustical noise. Consequently, EVs as well as working place noise have become major concerns, affecting the health of individuals. Efficiency of dc link use is improved by Space Vector Pulse Width Modulation (SVPWM). Yet, SVPWM is not efficient in lowering acoustical noise. Different RPWM techniques can lower acoustic noise. Still, the lower degree of randomisation makes the noise reduction difficult. This work presents a Hybrid Dual Random PWMs (HDRPWMs) based Alternate Inverter Switching (AIS) strategy for Slip-Angle Controlled Direct Torque Control of an Open End Winding IM Drive (OEWIMD). This technique is aimed to lower the acoustical noise for EVs. The intended PWMs seek to show how well HDRRPWMs distribute the acoustical noise spectra in contrast to conventional techniques.
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Kleizienė, Rita, Ovidijus Šernas, Audrius Vaitkus, and Rūta Simanavičienė. "Asphalt Pavement Acoustic Performance Model." Sustainability 11, no. 10 (2019): 2938. http://dx.doi.org/10.3390/su11102938.
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Low-noise pavements are used as an effective method of traffic noise mitigation. Low-noise pavements reduce the noise that arises due to interactions between tires and road surfaces (tire/road) via the implementation of three main components: low pavement roughness, negative pavement texture, and a high pavement air-void content. The tire/road noise reduction capabilities of the wearing layer vary depending on the aggregate type, gradation, bitumen and air-void content, and density. Consequently, the demand for an accurate tire/road noise prediction model has arisen from the design of asphalt mixtures. This paper deals with how asphalt mixture components of the wearing layer influence tire/pavement noise reduction and presents a model for tire/road noise level prediction based on the asphalt mixture composition. The paper demonstrates that the noise reduction level of low-noise asphalt pavements is dependent on the composition of the asphalt mixture. Asphalt wearing layer mixture composition parameters were tested in the laboratory from cores taken from 18 road sections, where acoustic properties were measured using a close-proximity (CPX) method. The proposed linear model is based on the bitumen amount, the air-void content of the mixture and aggregate shape and involves materials that comply with the general requirements for high-quality asphalt mixtures. The model allows for the prediction of the tire/road noise level at the asphalt mixture design stage using asphalt mixture components and volumetric properties. The proposed model is the first stage in the building of a complex model with a much wider range of low-noise asphalts components, pavement profile depth and CPX-value relationships.
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Cauchy, Pierre, Pierre Mercure-Boissonnault, Cécile Perrier de la Bathie, et al. "Characterization, understanding, and mitigation of underwater noise radiated by ships in the St. Lawrence Estuary." Journal of the Acoustical Society of America 155, no. 3_Supplement (2024): A347. http://dx.doi.org/10.1121/10.0027781.
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Underwater noise generated by commercial traffic is the main source of anthropogenic noise pollution at low frequencies, increasingly present at a global scale and of critical interest in the St. Lawrence Estuary (eastern Canada), where a rich biodiversity meets the shipping corridor linking the Great Lakes to the Atlantic Ocean. The Marine Acoustic Research Station (MARS, www.projet-mars.ca/en) is an applied research project dedicated to characterizing, understanding, and mitigating underwater traffic noise, contributing to the global effort of improving cohabitation between human activities and marine life. A cutting edge marine acoustic observatory has been specifically designed to collect high-quality measurements of the underwater noise radiated by ships. It is deployed yearly since 2021, operating during the ice-free season. A database of over 2000 measurements representative of the underwater noise radiated by the fleet operating in the St Lawrence Estuary has been collected, with a demonstrated repeatability of less than 1.5 dB which confirms the ability of the observatory to effectively assess the efficiency of noise reduction measures. The MARS database supports the development of a noise prediction model and provides feedback to shipowners and relevant information regarding the St. Lawrence fleet to the government for future underwater vessel noise reduction targets.
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Ranpise, Ramesh B., and Bhaven N. Tandel. "Urban road traffic noise monitoring, mapping, modelling, and mitigation: A thematic review." Noise Mapping 9, no. 1 (2022): 48–66. http://dx.doi.org/10.1515/noise-2022-0004.
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Abstract This article analyses the most recent studies on urban traffic noise. About 67 relevant articles on urban road traffic noise and its mitigation strategies were preferred for a critical review. Only 5.97% of items describe how to monitor and record the noise measurement for urban roads, while 7.46% of articles enumerated urban traffic noise pollution exposure. 29.85% of articles proposed a model to evaluate noise reduction effects and predict the noise level. Also, many articles reported noise map generation and its analysis. 56.71% of articles described the noise mitigation strategies in detail, concerning noise control by green vegetation, land use planning, low noise tire and pavement material, noise reduction through façade shielding. Noise pollution standards are being breached in all areas. There is a need for the proper implementation of rules and regulations. Therefore, noise mitigation strategies such as designing noise barriers and other noise control materials are needed. Finally, it is summarized that economic and low-cost optimized noise pollution mitigation strategies like ingeniously made noise barriers, vegetation and landscaping are need of the hour for urban areas of developing countries.
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Lloyd, Joshua, Cole Ludwikowski, Derek Phansalkar, Cyrus Malik, and Chen Shen. "3D printed acoustic metamaterial filters for the mitigation of inaudible ultrasound attacks on smart speakers." Journal of the Acoustical Society of America 153, no. 3_supplement (2023): A197. http://dx.doi.org/10.1121/10.0018642.
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Acoustic metamaterials have shown great potential in manipulating acoustic waves with a small footprint and versatile functionality. While their usefulness has been demonstrated in many fields including noise reduction and biomedical ultrasound, not many studies have been done in the field of audible acoustics and speakers. In this work, we show that an acoustic metamaterial-based filter can enhance the security of smart speakers, which are susceptible to inaudible ultrasound attacks due to the shadow effect of the microphones. The filter contains several resonant unit cells which collectively modulate the received signals in the ultrasound spectrum and, thus, mitigate inaudible attacks on smart speakers. On the other hand, normal audible signals are not affected and, therefore, regular functionality is not disturbed. The filtering effect is verified numerically using finite element analysis. Measurements are performed to validate the concept, where it is shown that inaudible ultrasound attacks are effectively blocked when the 3D-printed metamaterial filters are installed. This demonstration shows a possible way to apply acoustic metamaterials in consumer electronics such as smart speakers.
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QIAO, Xiaoru, and Yatsze CHOY. "Environmental noise reduction by sonic crystals barrier." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 9 (2024): 2482–91. http://dx.doi.org/10.3397/in_2024_3189.
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In order to reduce unpleasant effects on human health in environment, recent research has moved towards low-frequency and broadband noise mitigation. However, traditional noise barriers have several common shortcomings: airflow blocking, inefficient noise reduction, visual obstruction. Inspired by the classic design of sonic crystals (SCs), the basic C-shaped unit is improved to replace the conventional vertical outdoor barriers with a compact size. This paper explores the acoustic performance of the shadowed-C-shaped SC both numerically and experimentally. The simulation results show that this novel design can achieve broader band gap in the range below 5000Hz, especially at the resonant frequencies, the transmission coefficients approach to zero. Experiments are carried out with a full-scale model to evaluate the practical application of SC as noise barriers. It is verified that there is a good performance of insertion loss in broadband which is basically consistent with the simulation results.
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Kozak, Petr, Ondrej Dasek, Radka Matuszkova, and Michal Radimsky. "Low-Noise Asphalt Pavements in Urban Areas." Applied Mechanics and Materials 858 (November 2016): 282–86. http://dx.doi.org/10.4028/www.scientific.net/amm.858.282.
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Current requirements for the reduction of the noise pollution in inhabited areas are constantly increasing. Acoustic wearing courses represent the real measures how to directly mitigate sources of road traffic noise created by a tire/road contact. Directly reduced noise emissions created by a tire/road contact don't need further mitigation by expensive noise barriers. Noise emissions on two different types of wearing courses of asphalt mixtures (Asphalt concrete for very thin layers and Low-noise stone mastic asphalt) were measured using the specialized device operating on the basis of CPX (Close Proximity method) and compared with the standard mixture of Asphalt concrete. Differences were between 1 dB and 5 dB depending on the wearing course and the vehicle speed. The efficiency of the low-noise asphalt pavements was also compared with the initial costs of the pavements. The economical evaluation confirmed that the initial costs of the acoustic wearing courses are higher than the costs of the standard asphalt concrete mixture. However the noise reduction by 1 dB using the asphalt concrete for very thin layers increases the costs just by 350 USD (considering the same length and width of the road segment), which makes acoustic wearing courses the economically efficient noise reducing measure.
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YUEN, Gary K. C., and David B. K. YEUNG. "Investigation on enhancement of noise reduction of partially open windows and balconies through mock-up test." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 10 (2024): 1977–83. http://dx.doi.org/10.3397/in_2024_3111.
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Application of Acoustic Windows and Acoustic Balconies is a recent trend in Hong Kong to mitigate road traffic noise impact. In severe situations, enhancement is needed for the mitigation measures to provide additional improvement in acoustic performance. The performances of several common enhancements including micro-perforated absorber panels, perforated absorption panels, and balcony sidewalls are investigated through 1:1 mock-up test. The mock-up test aimed to mimic the actual situation, by referencing the spatial relationship between line sources and receivers. International standards are followed in the mock-up test, including ISO 16283-3: 2016 for microphone setting-out and BS EN 1793-3 for normalized traffic noise spectrum. Based on the mock-up test results, the research revealed that the enhancements' performance changes with line source orientation and suggested the optimum usage of enhancements.
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Bogoi, Alina, Grigore Cican, Laurențiu Cristea, Daniel-Eugeniu Crunțeanu, Constantin Levențiu, and Andrei-George Totu. "Comparing a New Passive Lining Method for Jet Noise Reduction Using 3M™ Nextel™ Ceramic Fabrics Against Ejector Nozzles." Technologies 13, no. 7 (2025): 295. https://doi.org/10.3390/technologies13070295.
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This study investigates the complementary noise control capabilities of two passive jet noise mitigation strategies: a traditional ejector nozzle and a novel application of 3M™ Nextel™ 312 ceramic fabric as a thermal–acoustic liner on the central cone of a micro turbojet nozzle. Three nozzle configurations, baseline, ejector, and Nextel-treated, were evaluated under realistic operating conditions using traditional and advanced acoustic diagnostics applied to data from a five-microphone circular array. The results show that while the ejector provides superior directional suppression and low-frequency redistribution, making it ideal for far-field noise control, it maintains high total energy levels and requires structural modifications. In contrast, the Nextel lining achieves comparable reductions in overall noise, especially in high-frequency ranges, while minimizing structural impact and promoting spatial energy dissipation. Analyses in both the time-frequency and spatial–spectral domains demonstrate that the Nextel configuration not only lowers acoustic energy but also disrupts coherent noise patterns, making it particularly effective for near-field protection in compact propulsion systems. A POD analysis further shows that NEXTEL more evenly distributes energy across mid-order modes, indicating its role in smoothing spatial variations and dampening localized acoustic concentrations. According to these results, ceramic fabric linings offer a lightweight, cost-effective solution for reducing the high noise levels typically associated with drones and UAVs powered by small turbojets. When combined with ejectors, they could enhance acoustic suppression in compact propulsion systems where space and weight are critical.
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Pingle, Pawan, Gloria Pignatta, and Samuele Schiavoni. "Unifying low and high-frequency noise mitigation: A novel dual noise barrier approach." Journal of the Acoustical Society of America 154, no. 4_supplement (2023): A65. http://dx.doi.org/10.1121/10.0022815.
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Road highways and urban areas often employ noise barriers to shield residential areas from excessive traffic noise. Despite continuous efforts, developing materials for noise barriers that can effectively mitigate noise across a wide frequency range is still a challenge. Specifically, creating a single material capable of attenuating both low and high-frequency noise has proven to be a daunting task. Current practices incorporate porous materials for absorbing low-frequency noise at specific locations. To address this limitation and offer a technique for traffic noise reduction, this research proposes a novel approach utilizing two hindrances: pores for low-frequency and bristles for high-frequency sound waves. An ANSYS Harmonic Acoustic module simulation was conducted to assess the proposed technique's effectiveness. The simulation encompassed geometry definition, material selection, boundary condition constraints, meshing, and analysis. The results indicate a significant reduction in noise at high frequencies (16 000 Hz) of approximately 30 dB, decreasing from 101.4 to 68.1 dB. This demonstration showcases the potential of a staggered arrangement of bristles and pores to handle a wide range of frequency content and effectively mitigate both low and high-frequency traffic noise. The novel dual noise barrier approach offers a promising solution to combat diverse traffic noise challenges, providing a more peaceful soundscape for urban residents.
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Zhang, Ziyan, Selin Yaman, Mohamad Salameh, Suryadev Singh, Chengxiu Chen, and Mahesh Krishnamurthy. "Effectiveness of Power Electronic Controllers in Mitigating Acoustic Noise and Vibration in High-Rotor Pole SRMs." Energies 14, no. 3 (2021): 702. http://dx.doi.org/10.3390/en14030702.
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This paper presents a comparative evaluation of power electronic control approaches for vibro-acoustic noise reduction in High Rotor-Pole Switched Reluctance Machines (HR-SRM). It carries out a fundamental analysis of approaches that can be used to target acoustic noise and vibration reduction. Based on the comprehensive study, four candidates for control have been identified and applied to the HR-SRM drive to evaluate their effectiveness and identify challenges. These four methods include phase advancing, current shaping based on field reconstruction, and random hysteresis band with and without spectrum shaping. The theoretical background, implementation, and vibro-acoustic noise reduction performance of each method are presented in detail. Comparative studies from simulation and experimental measurements have been used to identify the most effective solution to acoustic noise and vibration reduction in HR-SRM configuration.
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KONE, Tenon Charly, Sebastian GHINET, Panneton RAYMOND, and Anant GREWAL. "Structured acoustic materials for mitigating low-frequencybroadband aircraft noise: transfer matrix method." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 10 (2024): 1817–26. http://dx.doi.org/10.3397/in_2024_3084.
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This study investigates, by numerical modeling, the mitigation of low-frequency broadband aircraft noise using a structured assembly of acoustic materials using the Transfer Matrix Method. The prevalence of low-frequency aircraft noise poses challenges to environmental sustainability and passenger comfort. The investigation focuses on an approach that employs strategically arranged structured acoustic materials to attenuate undesirable noise frequencies. The Transfer Matrix Method is used to model the acoustic behavior of the structured assembly, enabling a comprehensive analysis of sound transmission and absorption properties. This method supports the design and optimization of the assembly. The performance of the structured assembly to selectively attenuate low-frequency broadband noise is assessed through numerical simulations. The paper discusses implications for aircraft design, considering factors such as weight and cost. The benefits for environmental impact and passenger experience are also explored. Challenges and limitations in the implementation of structured acoustic materials are examined. The configuration studied presents an assembly of structured metamaterials arranged in series and in parallel which are integrated into a layer of glass wool. Present research contributes to the development of sustainable solutions for low-frequency aircraft noise. The structured assembly analyzed shows promise for significant noise reduction while considering practical constraints.
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Syed Sibtain Khali. "Comprehensive Insights into Noise Mitigation for Automatic Speech Recognition Systems." Journal of Information Systems Engineering and Management 10, no. 35s (2025): 357–71. https://doi.org/10.52783/jisem.v10i35s.6012.
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Introduction: It is a comprehensive analysis of the advancements in Automatic Speech Recognition (ASR) systems in the presence of environmental noise, focusing on the challenges posed by various noise types and the evolution of noise mitigation strategies. Environmental noise significantly degrades ASR performance, leading to increased Word Error Rate (WER). The study categorizes background noise available during acoustic production sources for different kinds of surroundings and emphasizes the need for robust noise identification to enhance ASR efficiency. Various mitigation strategies including deep learning techniques, noise reduction algorithms, and model adaptations are explored, along with their effectiveness in real-time applications. This review adheres to the PRISMA guidelines to synthesize literature from peer-reviewed journals, identifying key methodologies adopted for noise recognition and suppression from 2010 to the present. Additionally, it outlines the transition from traditional feature-based methods to modern deep learning approaches such as Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs), which facilitate improved noise classification and enhance speech intelligibility in challenging environments. The review highlights ongoing challenges and future research directions aimed at optimizing ASR systems for diverse applications in socio-technological contexts.
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Stark, Callum, and Weichao Shi. "Hydroacoustic and hydrodynamic investigation of bio-inspired leading-edge tubercles on marine-ducted thrusters." Royal Society Open Science 8, no. 9 (2021): 210402. http://dx.doi.org/10.1098/rsos.210402.
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Underwater radiated noise (URN) has a negative impact on the marine acoustic environment where it can disrupt marine creature's basic living functions such as navigation and communication. To control the ambient ocean noise levels due to human activities, international governing bodies such as the International Maritime Organization (IMO) have issued non-mandatory guidelines to address this issue. Under such framework, the hydroacoustic performance of marine vehicles has become a critical factor to be evaluated and controlled throughout the vehicles' service life in order to mitigate the URN level and the role humankind plays in the ocean. This study aims to apply leading-edge (LE) tubercles of the humpback whales’ pectoral fins to a benchmark ducted propeller to investigate its potential in noise mitigation. This was conducted using CFD, where the high-fidelity improved delayed detached eddy simulations (IDDES) in combination with the porous Ffowcs-Williams Hawkings (FW-H) acoustic analogy was used to solve the hydrodynamic flow field and propagate the generated noise to the far-field. It has been found that the LE tubercles have shown promising noise mitigation capabilities in the far-field, where the OASPL at J = 0.1 was reduced to a maximum of 3.4 dB with a maximum of 11 dB reduction in certain frequency ranges at other operating conditions. Based on detailed flow analysis researching the fundamental vortex dynamics, this noise reduction is shown to be due to the disruption of the coherent turbulent wake structure in the propeller slipstream causing the acceleration in the dissipation of turbulence and vorticity-induced noise.
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Kone, Tenon Charly, Sebastian Ghinet, Raymond Panneton, and Anant Grewal. "Case study: Sub-metamaterials for Broadband Aircraft Noise Reduction Across Low and High Frequencies." Noise Control Engineering Journal 73, no. 1 (2025): 95–105. https://doi.org/10.3397/1/37737.
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Controlling broadband noise across the entire frequency spectrum, from low to high frequencies, poses a significant challenge for the aerospace, transportation, and construction industries. Recent research has primarily focused on low-frequency noise control solutions using acoustic metamaterials, but these materials are often limited by their narrow-band resonances. This paper addresses this limitation by presenting a novel sub-metamaterial system that broadens the resonance frequency band from low to high frequencies through a parallel assembly of sub-metamaterials. The proposed system comprises an arrangement of structured metamaterials and Helmholtz Resonators embedded in a layer of glass fiber. By meticulously grouping individual resonant frequencies, this assembly effectively attenuates noise across the desired frequency range. Our research demonstrates promising potential for significant noise reduction within practical constraints, contributing to the development of durable solutions for aircraft noise mitigation over a broad frequency spectrum.
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Lu, King Kwong, Maurice Yeung, Kit Wong, and Fanni Lin. "Development on acoustic louvre to enhance the noise reduction performance of acoustic balconies." Journal of the Acoustical Society of America 154, no. 4_supplement (2023): A86. http://dx.doi.org/10.1121/10.0022886.
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A balcony in a domestic flat provides residents an outdoor living space as well as better ventilation to improve indoor air quality. However, balcony door when open for natural ventilation will allow outdoor noise transmit into the residential flat. Innovative acoustic balcony design by installation of sound absorptive panels onto the balcony ceiling and side walls of balcony has been implemented in Hong Kong for mitigating road traffic noise. Recently, combined balcony with an extension of utility platform for installation of air-conditioning outdoor unit has become popular. However, the parapet of the extension used a three-sided air grille with 70% permeability for heat dissipation purpose. Acoustically, the issue is noise leakage through the air grille comparing to a solid parapet. This paper discusses the development of acoustic louvres to replace the air grille in order to improve the noise reduction abilities of acoustic combined balconies. Several acoustic louvres of different configuration are developed. Validation of improvement in noise reduction of the acoustic combined balcony in a mock-up flat is conducted in accordance with ISO 16283-3.
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Totu, Andrei-George, Marius Deaconu, Laurențiu Cristea, Alina Bogoi, Daniel-Eugeniu Crunțeanu, and Grigore Cican. "Experimental Analysis of Acoustic Spectra for Leading/Trailing-Edge Serrated Blades in Cascade Configuration." Processes 12, no. 11 (2024): 2613. http://dx.doi.org/10.3390/pr12112613.
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This study aims to highlight the noise reduction achieved through the integration of serrated blades on the leading and trailing edges within a small-scale cascade configuration relevant to turbomachinery contexts. Experiments were conducted using a newly developed 3D-printed test bench, enabling both acoustic and aerodynamic measurements. Turbulence was generated using a rectangular grid positioned at two axial locations. Non-dimensional spectra were computed and compared with experimental data, showing good agreement over a wide frequency range. Significant noise reduction was observed in the 1000–3000 Hz band, despite the lack of optimization of turbulence and serration parameters. Leading-edge serrations were found to be effective at lower frequencies in the axial direction and at higher frequencies laterally. In contrast, trailing-edge serrations had a minimal impact above 3500 Hz, performing worse than the reference condition across a large frequency range. Nevertheless, for this initial iteration at a small scale, overall sound pressure level reductions of up to 1 dB were achieved with trailing-edge serrations and up to 1.5 dB with leading-edge serrations, underscoring their potential for noise mitigation in relevant applications.
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Wang, Wen-Yu, and Yuh-Ming Ferng. "Numerical model for noise reduction of small vertical-axis wind turbines." Wind Energy Science 9, no. 3 (2024): 651–64. http://dx.doi.org/10.5194/wes-9-651-2024.
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Abstract. Small vertical-axis wind turbines are a promising solution for affordable and clean energy, but their noise emissions present a challenge to public acceptance. Numerous blade designs have been aimed at reducing noise but often come with a decrease in wind turbine aerodynamic efficiency. In this study, the acoustic power and torque of a 5 kW vertical-axis wind turbine (VAWT) were simulated by using different mesh sizes and turbulence models. The simulated torque and noise of the turbine have significant sensitivity to the mesh size, so suitable mesh sizes were determined for the near-wall and rotating regions that can be used as a design reference for future turbines with similar operating conditions. The selection of the turbulence model was found to affect the predicted torque by about 10 % and the predicted tip noise by about 2 dB. The selected mesh size and turbulence model were then applied to simulating the effectiveness of three common noise mitigation techniques: a mask, deflector, and wall roughness. The results showed that deflectors are suitable for noise reduction of small VAWTs. This paper provides valuable information on simulating noise propagation from small VAWTs and the optimal noise reduction techniques.
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Chung, Andy W., and Wai Ming To. "Hybrid VR and physical kiosks for soundscape design in urban planning." Journal of the Acoustical Society of America 156, no. 4_Supplement (2024): A94. https://doi.org/10.1121/10.0035221.
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In response to the challenge of urban noise pollution, innovative noise mitigation measures, such as acoustic windows and balconies, have been developed to effectively reduce traffic noise while allowing natural ventilation. To engage stakeholders and demonstrate the effectiveness of these innovations, a physical kiosk equipped with an acoustic window was created, along with a complementary Virtual Reality (VR) experience. This setup aims to create a near-real perception of the sonic environment, allowing users to experience noise reduction capabilities along with other sensory effects. Through this case study, we explore the practical application of VR and physical models as powerful tools for soundscape interventions and stakeholder engagement. By showcasing the integration of these technologies in urban planning, we provide insight into their potential to shape the future of soundscape design and policy development, emphasizing their role in creating healthier and more pleasant urban environments.
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Madasamy, P., Rajesh Verma, C. Bharatiraja, et al. "Hybrid Multicarrier Random Space Vector PWM for the Mitigation of Acoustic Noise." Electronics 10, no. 12 (2021): 1483. http://dx.doi.org/10.3390/electronics10121483.
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The pulse width modulation (PWM) inverter is an obvious choice for any industrial and power sector application. Particularly, industrial drives benefit from the higher DC-link utilization, acoustic noise, and vibration industrial standards. Many PWM techniques have been proposed to meet the drives’ demand for higher DC-link utilization and lower harmonics suppression and noise reductions. Still, random PWM (RPWM) is the best candidate for reducing the acoustic noises. Few RPWM (RPWM) methods have been developed and investigated for the AC drive’s PWM inverter. However, due to the lower randomness of the multiple frequency harmonics spectrum, reducing the drive noise is still challenging. These PWMs dealt with the spreading harmonics, thereby decreasing the harmonic effects on the system. However, these techniques are unsuccessful at maintaining the higher DC-link utilizations. Existing RPWM methods have less randomness and need complex digital circuitry. Therefore, this paper mainly deals with a combined RPWM principle in space vector PWM (SVPWM) to generate random PWM generation using an asymmetric frequency multicarrier called multicarrier random space vector PWM (MCRSVPWM). he SVPWM switching vectors with different frequency carrier are chosen with the aid of a random bi-nary bit generator. The proposed MCRSVPWM generates the pulses with a randomized triangular carrier (1 to 4 kHz), while the conventional RPWM method contains a random pulse position with a fixed frequency triangular carrier. The proposed PWM is capable of eradicating the high-frequency unpleasant acoustic noise more effectually than conventional RPWM with a shorter random frequency range. The simulation study is performed through MATLAB/Simulink for a 2 kW asynchronous induction motor drive. Experimental validation of the proposed MCRSVPWM is tested with a 2 kW six-switch (Power MOSFET–SCH2080KE) inverter power module-fed induction motor drive.
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Ho, Wilson, Wylog Wong, and Eric Chu. "Sheet Pile Tuned Mass Damper for Construction Noise Control." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 1 (2023): 6593–600. http://dx.doi.org/10.3397/in_2022_0995.
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Sheet piles are often used for underground retaining structures. For dense geology, vibratory driven method is more cost-effective than press-in driven method, but noisier. Conventional mitigations such as noise barrier or enclosure are not applicable due to the large size of pile wall (generally >12m high and >10m width). Acoustic camera images revealed that noise radiation was dominant at 630Hz to 2000Hz and mainly came from the sheet-pile wall rather than the vibratory exciter. Vibration response measurement showed the sheet piles had two major resonance modes at 1000 and 2000Hz. An innovative noise mitigation method was developed with 14 nos. of tuned mass dampers (TMD) distributed along a 5m long aluminum tube for vibration energy dissipation at the pile wall. Specific magnetic mounts were developed for quick and easy attachment of the TMDs at the construction site. In the site test, total 6 aluminum tubes (i.e., 84 TMDs) were mounted to the 1st, 2nd and 3rd piles adjacent to the driven pile on both sides. Vibration reduction was measured ~9 to 14dB at the pile wall. Noise reduction was measured 7 to 9dB(A) at 2 noise monitoring locations (~7m and ~22m from the pile wall).
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Wu, Han, Wangqiao Chen, Peng Zhou, et al. "Assessment and mitigation of the rotor noise for future urban air mobility vehicles." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, no. 4 (2023): 4201–8. http://dx.doi.org/10.3397/in_2023_0595.
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Multi-rotor configurations are often adopted in urban air mobility (UAM) designs. The aerodynamic noise of rotors is a significant source of the UAM vehicles, requiring systematic measurements and mitigation. To this end, a large-scale test rig is designed and built to enable the acoustic measurement of UAM rotor blades. The test rig is placed in an anechoic chamber with the size of 8.1 m (L) × 6 m (W) × 5.1 m (H). The aerodynamic force and noise of a pair of custom-designed blades with a radius of 0.5 m are measured. The rotational speed ranges from 600 to 1800 revolutions per minute. A zig-zag turbulator is applied on the blade surface to trip the boundary layer. The effect of the turbulator on rotor noise is negligible compared to the untreated case, indicating that the blade boundary layer is fully developed. Particulate roughness is then implemented on the blade surface to explore the potential of noise reduction for turbulent blade boundary layers. Results show that a reduction of 3 dB in high-frequency broadband noise can be achieved upstream and downstream of the rotor at 1800 RPM when the particulate roughness is applied on the leading-edge region of the blades.
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Barbalho, Bárbara Santos, Matheus Yusef Garavelli, and Armando de Mendonça Maroja. "Acoustic Pollution Assessment Caused by the Federal District Subway (Águas Claras)." Revista de Gestão Social e Ambiental 19, no. 7 (2025): e012749. https://doi.org/10.24857/rgsa.v19n7-004.
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Objective: This research primarily aimed to evaluate the environmental impacts of noise generated by subway operations on the population of Águas Claras, in the Federal District. Theoretical Framework: Transportation noise is recognized as the leading source of global sound pollution. According to the World Health Organization, it's the second-largest environmental problem affecting people, surpassed only by air pollution. In this context, environmental noise measurement and computational simulation, integrated with Geographic Information Systems (GIS), are fundamental tools for mitigating its effects, supporting the development of prevention and reduction plans, and raising public awareness about the issue. Method: The methodology employed was based on noise map simulations to determine sound pressure levels in both the study area and on the facades of buildings near the subway line. To complement these simulations, acoustic measurements were conducted in communities residing in areas adjacent to the tracks, providing essential data for analyzing the environmental noise impact on the population. Results and Discussion: A combined analysis of the noise maps and environmental measurements revealed that the equivalent sound pressure level during daytime hours exceeds the legally established limits in residences with a direct view of the subway line. Additionally, it was observed that sound levels exceeding 70 dB(A) are recorded in nearby residences during train passages. Research Implications: To reduce the disturbance caused by subway noise in residential areas, the construction of acoustic barriers along the line's margins is suggested. It's crucial that actions to decrease environmental noise in residences consider not only average levels but also the specific disturbance during train passages. Originality/Value: The assessment of the subway's acoustic impacts in the Federal District is of vital importance. It not only allows for understanding the current discomfort experienced by the population but also serves as a basis for planning future system expansions to minimize acoustic environmental impacts. It's imperative that authorities responsible for urban planning and transportation implement mitigation measures, such as installing acoustic barriers and using technologies that reduce track vibration in surface sections.
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Huisman, Marco, Louis Lederwasch, and René Smidt Lützen. "Bubble curtain modelling: analytical prediction of piling noise mitigation." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 5 (2021): 1142–51. http://dx.doi.org/10.3397/in-2021-1763.
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In order to mitigate underwater noise caused by pile driving, bubble curtains are widely used during offshore constructions. These form an impedance barrier to the acoustic pressure wave, and the resulting attenuation on the interface of water to bubbly water is the main driver behind the insertion loss that can be achieved. A secondary effect is energy absorption by bubble resonance; however, normal bubble sizes are such that the resonance frequency is considerably higher than the peak in the piling noise spectrum, rendering the resonance contribution to the overall insertion loss relatively small. The broadband insertion loss and sound level reduction spectra of bubble curtains are mainly determined on an empirical basis, comparing actual project data and noise monitoring results across sites. Although several efforts have been made to capture the noise mitigation by bubble curtains in numerical models, there is no straight-forward integrated modelling method available to quantify the influence of individual design and operational parameters. Using a number of assumptions and simplifications, this paper presents an analytical model for the frequency-dependent and broadband insertion loss achieved by bubble curtains, that combines both impedance and resonance effects.
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Sekunowo, O. I., B. O. Bolasodun, G. T. Oyedepo, and J. Y. Oluwole. "Noise Pollution Mitigation Study of Rice Husk-Ash Nanoparticle Reinforced Epoxy Resin Composites." Journal of Engineering Research 25, no. 1 (2020): 29–38. https://doi.org/10.52968/72018484.
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The menace of noise pollution to human health, knowledge dissemination and tranquil environment continues to increase daily. This is not unconnected with industrialisation and multiplicity of human activities hence the need for the development of eco-friendly materials capable of drastically reducing noise pollution. In this study, epoxy resin composites were synthesised using rice husk ash nanoparticles (RHANP) as reinforcement varied from 5-25 wt. %. The composites were characterised for acoustic capabilities and the results show desirable sound absorption of up to 71.6% sound decibel mitigation at 5-15 wt. % RHANP addition. This was demonstrated by the Noise Reduction Coefficient (NRC) of the composites in the range of 0.654-0.805 at sound frequencies of 2-6 kHz. This compare well with most conventional acoustic panels installed on the ceiling of hospitals, conference centres and lecture theatres. The composites were also characterised for relevant handling mechanical properties required to guarantee damage-free installation. The outcomes indicate 35.8 MPa flexural strength, 4.3 J impact energy and hardness of 25.1 HV. These levels of mechanical properties are adjudged sufficient for safe handling and durability in service. The contributions of the study will significantly impart comfortability at facilities such as hospitals and libraries that are prone to noise pollution. Furthermore, the outcomes of the study have the potential to engender cleaner environment, value addition and a boost to the nation’s Gross Domestic Product (GDP)
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Tekampe, Sabine, and Markus Oeser. "Assessing the Durability and Acoustic Performance of a Novel Two-Layer Pavement System." Sustainability 15, no. 23 (2023): 16475. http://dx.doi.org/10.3390/su152316475.
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In the quest for more sustainable pavement solutions, this study demonstrates the successful strengthening of a unique noise-reducing two-layer road surface. While existing noise-reducing pavements reveal high acoustic efficiency, they lack mechanical strength, and earlier research efforts addressed the optimization of the individual components of this system, and a comprehensive perspective on its integrated performance remained elusive. Therefore, this research bridges this knowledge gap through an in-depth laboratory evaluation, in which the requirements for the realization of a full-scale demonstrator were defined, followed by a comprehensive performance assessment in terms of acoustic and mechanical strength. The post-construction assessment reveals the system’s multifaceted strengths, considering noise reduction, resilience under heavy traffic, pavement deflections, and skid resistance, assessed by CPX measurements, accelerated pavement tests using the MLS 30, skid resistance tests employing the pendulum test, as well as the slow-moving longitudinal friction test (MicroGriptester) and falling weight deflectometer (FWD) measurements. Although the optimized system implies lower noise-reduction potential, it exhibits great strength compared to previous noise-reducing pavements. In general, the system offers viable noise mitigation solutions for urban highways, particularly in settings where traditional noise abatement measures are constrained by space. The insights from this study serve as a valuable reference for the development and evaluation of innovative road engineering materials and technologies.
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Lázaro, João, Matheus Pereira, Pedro Alves Costa, and Luís Godinho. "Performance of Low-Height Railway Noise Barriers with Porous Materials." Applied Sciences 12, no. 6 (2022): 2960. http://dx.doi.org/10.3390/app12062960.
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Rail transport is the most sustainable transportation mode, with the lowest energy consumption and carbon footprint. However, the noise induced by railway traffic in urban regions is a significant drawback and several reports point out the risks and the amount of people suffering from direct exposure to railway noise. One of the most used mitigation measures for railway noise is the implementation of noise barriers. Although they offer a significant reduction in noise levels, their height makes people feel enclosed. Therefore, in the case of railway infrastructure, the solution to the problem may lie in the use of barriers with a lower height placed close to the railway track. As the noise-forming mechanisms are mainly located at the track level, placing the barrier in a position close to the track allows mitigating rail noise without causing the problems identified above for the population in the vicinity. The purpose of this paper is to illustrate the development of a barrier solution to be used in a railway context through numerical modelling with the Boundary Element Method (BEM). The solutions developed were placed close to the track and have a low height. The geometry was defined so as to direct the energy back to the track to take advantage of the acoustic properties of the ballast. The addition of a porous granular material on the inner face of the barrier allows the control of reflections between the vehicle body and the barrier, increasing its acoustic efficiency. Finally, considering the most efficient solution, the insertion loss in a network of receivers located 10 m away from the track is analysed in order to study the noise reduction levels in a place where human receivers are usually located.
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YADAV, Prasad, Harshal BANKAR, and Nagesh WALKE. "LCV Vehicle in-cab noise prediction and reduction using SEA based simulation approach." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 5 (2024): 6545–50. http://dx.doi.org/10.3397/in_2024_3791.
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With increase in consumer demand vehicle OEMs are developing quieter vehicles at a design stage using acoustic simulation tools to reduce development cycle times avoiding costly proto builds and test iterations. Present work describes application of statistical energy analysis (SEA) simulation approach for in cab noise prediction and noise reduction through sound package optimization for LCV vehicle. In first step complete vehicle in-cab SEA model is prepared with baseline sound package concept. It consists of comprehensive definition of structural panels, interior and exterior cavities. Noise control treatment is modelled as multi-layer poro-elastic materials. Airborne noise excitations for sources engine, transmission, intake and exhaust muffler are applied. Source strengths for above sources were derived from dyno-coupled powertrain noise tests in the anechoic chamber. Load case of rated speed was considered neglecting tire and wind noise during simulation. Contribution analysis was carried out to find out sensitivity of different panels on interior noise at various frequencies. It was observed that bottom middle floor panel and rear glass panel were major noise contributors. Noise mitigation was carried out by optimizing floor panel sound package and intake air filter within given space constraints. These modifications resulted in overall 2 dB in-cab noise reduction
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Yu, Fu-Yang, Zhen-Hua Wan, Ya-Sen Hu, De-Jun Sun, and Xi-Yun Lu. "Effects of leading-edge serration shape on noise reduction in rod-airfoil interactions." Journal of the Acoustical Society of America 157, no. 1 (2025): 215–33. https://doi.org/10.1121/10.0034845.
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Leading-edge serrations inspired by owls exhibit the capability to control airfoil-turbulence interaction noise, but the design principle of the serration shape is still an open issue. To this end, we designed five types of serration shapes with different combinations of curvature, namely, triangular, ogee, anti-ogee, feather-like, and anti-feather-like. These curves are applied to serrated modifications with different bluntness levels (sharp or blunt) and amplitudes (0.05, 0.075, and 0.1 chord length). Considering these serration shapes, 30 cases with various curved types, bluntness levels, and amplitudes are investigated using compressible large-eddy simulation and the acoustic analogy of Ffowcs-Williams and Hawkings on a rod-airfoil configuration. The outcomes reveal a general trend where increased amplitude and blunted serrations are more effective in noise mitigation. Notably, the blunt feather-like (FB) serrations demonstrate the maximum noise reduction capacity across all amplitude levels, decreasing the overall sound power level by up to 2.1 dB. Through multi-process acoustic analysis, source characteristics responsible for generating noise are diagnosed. It is found that noise reduction primarily stems from the change in the source distribution and destructive interference among sound sources, consistent with prior studies. Generally, the serration shape would significantly affect the source distribution and sound interference without altering the fundamental noise reduction mechanisms. The FB shape exhibits the highest concentration of sources at its peaks and roots among all shapes. The presence of concentrated sources in these locations enhances destructive interference, effectively reducing noise emissions. The superior noise-reduction feature of FB serrations should be attributed to both the concentration of sources and the destructive interference. This extensive examination underscores the importance of serration design, especially the potential of FB serrations, in noise control strategies for rod-airfoil configurations, contributing to advancements in aeroacoustic engineering.
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Shen, Yingyin, Yuanqing Bai, Xiao Liu, and Bin Zang. "Drone Noise Reduction Using Serration–Finlet Blade Design and Its Psychoacoustic and Social Impacts." Sustainability 17, no. 8 (2025): 3451. https://doi.org/10.3390/su17083451.
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Unmanned aerial vehicles, particularly drones, have been increasingly deployed for different tasks in the community. They have become an important part of the economic and social benefits that society is exploiting from modern technology development. However, efforts are still required to further develop technologies which can mitigate the negative impacts. Among them, drone noise is considered a major health concern for the community. The present study undertakes an experimental investigation of the effectiveness of blade modifications on drone noise in an aeroacoustic wind tunnel facility. A quadcopter drone is programmed to operate in both hover and forward flights. Three modified blade configurations, including trailing-edge serrations combined serration–finlets, and an unmodified (baseline) blade, are manufactured. The far-field noise signals are recorded by two polar microphone arrays to quantify both the magnitude and directivity. The results show that all modified blades are able to reduce the drone noise at mid-to-high frequencies in both hover and forward flights, and this leads to a noticeable reduction in the overall sound pressure level. More importantly, the combined serration–finlet configuration outperforms all the other blades. Psychoacoustic analysis is also performed using the far-field acoustic time series. Interestingly, only the serration–finlet combination demonstrates a consistent reduction in the psychoacoustic annoyance levels, suggesting that it is important to use metrics from both acoustic and psychoacoustic analysis when developing noise mitigation strategies in the socio-economic context.
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Gramowski, Christoph, and Roxana Donner. "Assessment of the Noise Reduction Impact from Application Restrictions on Rail Dampers." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 3 (2023): 4764–72. http://dx.doi.org/10.3397/in_2022_0689.
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In the last decades, rail dampers had become a commonly used rolling noise abatement measure at several mainline and metro networks. Rolling noise reductions outdoor/indoor up to 4/8 dB had been found. While the beginning of damper application was started with multiple test sections, infrastructure managers had raised installation restrictions from other related technology departments like signaling and communication. This is leading to defined sections where one rail has to remain partially free from dampers or the track has to remain completely free from dampers. These sections become relevant when the damper application is caused by noise tackling action plans. Therefore, the acoustic impact was assessed by a) laboratory test track analysis (partially free) and b) environmental noise prognosis software (completely free). It is shown, that also for a partially free rail, a cancellation of the noise reduction can be expected for single 1/3 octave frequencies. This can be relevant for the overall noise emission. The effect from the completely free rail is much larger due to noise increases at several immission points. Railway noise mitigation has to consider these results or, if possible, the rail damper technology has to be improved to avoid these restricted sections.
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SCHINDLER, Johannes, Arthur BRAUNSCHWEIG, Rolf HUWYLER, and Erik BüHLMANN. "How sustainable are low-noise pavements? Answers from a life-cycle-assessment including the use-phase and noise mitigation of typical Swiss pavements." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 8 (2024): 3732–43. http://dx.doi.org/10.3397/in_2024_3363.
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Despite continuous efforts to reduce road noise emissions, road noise is still the dominant source of noise in Switzerland. Low-noise pavements are an effective measure for road noise mitigation, but besides their higher cost, their major drawback is a reduced service lifetime as compared to conventional pavements. How do these arguments compare in a comprehensive view? To address this question, we performed a cradle-to-grave life-cycle-analysis of four different pavement types: a conventional pavement as reference, two types of semi-dense low-noise pavements and an acoustically optimized type of asphalt concrete. Besides the needed raw materials, the construction, maintenance and demolition, this life-cycle-analysis also includes the use-phase of the road. Thus, the noise mitigation (based on latest acoustic ageing models) and changes in fuel consumption (based on rolling resistance) are included in the assessment. We evaluate the results in the dimensions of ecological scarcity, greenhouse gas emissions, primary energy consumption and life cycle costs. The impact assessment method "Swiss ecological scarcity" allows to weight noise emissions and fuel consumption directly against resource demands of the different pavement types. Our results show that in densely populated areas, the noise reduction and energy savings clearly outweigh the increased resource demand of low-noise pavements.
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Juan, Shiang-I., and Lucky S. Tsaih. "An overview of green roof acoustic performance." Journal of the Acoustical Society of America 155, no. 3_Supplement (2024): A283. http://dx.doi.org/10.1121/10.0027517.
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This comprehensive review provides an in-depth examination of the acoustic performance of green roofs within urban and built environments over the past 15 years. Green roofs, characterized by their vegetative cover and substrate layers, offer a multifaceted solution to address challenges associated with urban noise pollution. The objective of this review is to synthesize existing literature, emphasizing key studies and methodologies employed to assess the noise reduction and sound isolation capabilities of green roofs. Factors influencing green roof acoustic performance, such as plant species selection in the plant layer, soil distribution, moisture content, and compaction level in the vegetation layer, as well as the overall roof design in terms of shapes and building configuration, are discussed in detail. Additionally, the impact of overall roof design, including shapes and building configuration, is explored. The relevant sound absorption coefficient and insertion loss values, drawn from the existing literature, will be reported. By systematically analyzing empirical findings, this overview offers valuable insights into the potential of green roofs as sustainable components for noise mitigation in building construction, contributing to the development of more resilient and harmonious urban landscapes.
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SHARMA, Ashutosh, Corinna KRAASCH, and Anna WEGNER. "Acoustic evaluation: microphone array measurements on a multi-megawatt individual pitch control wind turbine." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 270, no. 8 (2024): 3376–87. http://dx.doi.org/10.3397/in_2024_3318.
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As rotor diameters of wind turbines approach 200 m, aerodynamic noise becomes a significant issue, especially for onshore turbines. The rapid expansion of wind energy has led to increased concerns regarding the noise generated by wind turbines particularly in proximity to residential areas. This study investigates the noise emissions from a full-scale multi-megawatt individual pitch control (IPC) onshore wind turbine, with rotor diameter of 158 m and a hub height of 120 m, across 12 scenarios-six upstream and six downstream. The wind turbine under investigation operates under both IPC and non-IPC modes. Utilizing a microphone array and beamforming algorithm techniques, we conducted comprehensive acoustic measurements to analyses the noise sources and their characteristics. Our findings indicate that turbine operating in IPC mode produces higher sound pressure levels dB (A-weighted) as compared to the turbine under non-IPC modes. This observation emphasizes the need for a balanced approach in wind turbine operations, considering both load reduction and noise mitigation.
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Redonnet, Stephane. "Further assessment of a time domain impedance boundary condition for the numerical simulation of noise-absorbing materials." International Journal of Aeroacoustics 20, no. 8 (2021): 927–58. http://dx.doi.org/10.1177/1475472x211052701.
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In regard to the mitigation of environmental noise across major industry sectors, the present study focuses on the numerical prediction of passive noise reduction devices. Here, it is further explored how the noise attenuation induced by locally reacting noise absorbing materials (also called acoustic liners) can be simulated using a time domain highly accurate Computational AeroAcoustics (CAA) method. To this end, it is assessed how a classical Time Domain Impedance Boundary Condition (TDIBC) can effectively model acoustic liners of practical interest, including when the latter are exposed to realistic conditions (grazing flow and noise excitation). The investigation consists in numerically reproducing two experimental campaigns initially performed at NASA Langley Research Center. Two different materials are considered (honeycomb superimposed with perforate or wiremesh resistive face-sheet), each being characterized by a specific noise attenuation behaviour ( e.g. dependency on the flow conditions and/or noise excitation). Each material is tested under various flow conditions ( e.g. grazing flow of Mach up to 0.5) and/or noise source excitation ( e.g. multiple tones of level up to 140 dB each). The results demonstrate the ability of the underlying CAA/TDIBC approach to simulate realistic acoustic liners in non-trivial configurations, with enough physical accuracy ( e.g. correct capture of the noise attenuation characteristics) and numerical robustness ( e.g. absence of instabilities). The study also reveals that, independent from the CAA/TDIBC approach itself, some specific pre-processing tasks (e.g. impedance eduction and subsequent TDIBC calibration) may play a bigger role than expected, in practice.
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Guy, Marc-André, Kamal Kesour, Olivier Robin, Julien St-Jacques, and Mathis Vulliez. "Evaluation of the performance of technologies for reducing ships' machinery noise using a small-scale ship-like structure in a Water Basin." Journal of the Acoustical Society of America 155, no. 3_Supplement (2024): A348—A349. http://dx.doi.org/10.1121/10.0027786.
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Ocean ambient levels have increased in the last decades, especially in the low-frequency domain (under 500 Hz). This increase is partly due to underwater radiated noise (URN) from commercial ships. Excessive URN harms marine life and is, therefore, considered a pollution that needs to be reduced. At low speeds, machinery is the primary noise source on ships. Mitigation technologies exist to limit machinery’s contribution to URN. While implementing these technologies is costly, a lack of quantitative data regarding their exact performances usually results in limited concrete ship applications since the cost-to-benefit ratio is imprecise. This study aims to quantify better the performance of standard noise mitigation technologies using a small-scale ship-like structure in a water basin. The basin’s acoustic field is first characterized with and without the structure. The structure is then equipped with different mitigation technologies. A loudspeaker and a vibration shaker are fed with pink noise or measured signals on actual machinery. Hydrophones, microphones, accelerometers, and force sensors measure the response in the basin and on the structure. The performance of each tested technology is evaluated and ranked in terms of URN reduction. The relative contributions of airborne and structure-borne transmission paths on URN are also examined.
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Sharma, Gyani Shankar, and Abhijit Sarkar. "Directivity-Based Passive Barrier for Local Control of Low-Frequency Noise." Journal of Theoretical and Computational Acoustics 26, no. 04 (2018): 1850012. http://dx.doi.org/10.1142/s2591728518500123.
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This work concerns with improving the transmission loss offered by a noise barrier separating two acoustic spaces in the low-frequency range. A novel concept of local mitigation of the transmitted noise at a target receiver location is presented by controlling the directivity of the transmitted noise through a point mass attachment on the barrier surface. Mass attachment at an arbitrary location is shown to increase the noise transmission. Optimal locations of the mass to minimize the sound transmission in the normal, oblique and tangential directions to the barrier are obtained. Optimal placement of the mass results in a major transmission reduction around the target location, much more than achievable by a uniform distribution of the mass over the barrier. Total transmitted pressure is also reduced; however, local reduction around the target location is much higher. The effects of variation in the excitation frequency and magnitude of the attached mass are investigated.
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Havran, Volodymyr, and Mariia Orynchak. "SMART NOISE POLLUTION MANAGEMENT USING AWS IOT CORE AND CLOUD INTEGRATION." Computer Design Systems. Theory and Practice 7, no. 1 (2025): 73–80. https://doi.org/10.23939/cds2025.01.073.
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Urban and rail transport noise pollution is an increasing concern due to its negative impact on public health, including cardiovascular diseases, sleep disturbances, and cognitive impairments (WHO, 2018). Traditional noise monitoring systems, which rely on static measurements, lack real-time adaptability and struggle to accurately classify noise sources in dynamic environments. This study explores the application of AWS IoT Core in smart acoustic monitoring systems to enhance noise detection, classification, and mitigation. By integrating AWS IoT Core with advanced noise sensors and spectrum analyzers, real-time noise data can be securely transmitted, processed, and analyzed in the cloud. AWS IoT Core enables continuous data collection and facilitates predictive modeling, improving noise classification accuracy and supporting proactive noise reduction strategies. The study focuses on leveraging AWS IoT Core for real-time noise monitoring, automated noise classification, and data-driven urban planning, ensuring more effective and scalable noise management solutions. Furthermore, AWS IoT Core’s ability to connect and manage thousands of IoT-enabled noise monitoring devices provides a foundation for smart city infrastructure. The research highlights key challenges and opportunities in integrating cloud-based noise monitoring systems, emphasizing the role of AWS IoT Core in optimizing urban noise management, improving public health outcomes, and supporting sustainable city development. Through adaptive noise mitigation strategies and enhanced decision-making, AWS IoT Core offers a scalable and efficient approach to addressing noise pollution in modern urban environments.
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Bushkovsky, V. A., and Yu A. Yegorov. "Blade number effect upon high-frequency marine propulsor noise: model test data." Transactions of the Krylov State Research Centre 4, no. 402 (2022): 41–48. http://dx.doi.org/10.24937/2542-2324-2022-4-402-41-48.
Full textAbstract:
Object and purpose of research. This paper discusses blade systems of propellers and water jets. The purpose of the study was to outline the ways to mitigation of high-frequency non-cavitation noise of marine propulsors. Subject matter and methods. The study analyses Russian and foreign publications on aero- and hydroacoustics of propellers and foil systems. It also determines the parameters of turbulent boundary layer on propeller blades with respect to its effect upon propeller noise radiation. Noise assessment methods obtained for aerodynamics of foil systems have been applied to marine propulsors. Main results. Theoretical studies have shown that marine propellers with fewer blades tend to have lower radiation of high-frequency noise. Direct noise measurements of propulsor models performed under this study have confirmed this trend. Conclusion. In contrast to the low-frequency propeller noise, high-frequency acoustic radiation can be achieved through reduction of propeller blade number.