bluuebunny/crossref_metadata_2025 huggingface dataset:
Measures to abate railway noise
Authors: WEINANDY Rene , APPEL Percy
Published: October 2024

An important environmental issue in densely populated areas, such as Germany or France, is the problem of noise. Traffic noise from cars, railway vehicles and airports located in close proximity to the city is not only annoying for residents; it also leads to serious health issues and
has an enormous negative economic impact. Unlike road traffic noise, which occurs virtually everywhere, rail traffic noise is much more localized to individual transport corridors. However, depending on the type of train and the volume of trains, high levels of noise can be generated, especially
along freight corridors on which most of the rail traffic is at night. One example is the Middle Rhine Valley, which is part of the European freight corridor between Rotterdam and Genoa. In many places along this corridor, the noise levels are essentially higher than those considered desirable
to maintain good health. The noise caused by rail traffic is therefore the ecological Achilles heel of the railway. However, there are measures for the reduction of noise emitted by rail traffic. In a recent research project, the German Environment Agency evaluated technical, operational and
legal measures to abate the railway noise.
Low cost modelling tools for the design of additively manufactured acoustic materials
Authors: KENNEDY John , WELDON Sophie
Published: October 2024

Additive manufacturing (AM) methods have unlocked new capabilities in the design of acoustic materials and their topologies. This has enabled the design of devices with breakthrough performance in sound absorption and insulation while achieving subwavelength characteristics. However,
material fabrication through AM presents its own challenges. These challenges include inherent defects which can be specific to the printing method employed. Examples of defects in low-cost AM include void formation, surface roughness and poor bonding between layers. Each of these features
of AM have different acoustic impacts which may degrade the performance of a design. To optimize the production of additively manufactured acoustic materials it is imperative that designers can exploit features, such as surface roughness, to enhance rather than degrade the overall material
performance. The aim of this paper is to investigate the effects of surface roughness in extrusion-based AM on acoustic material performance. A novel, low-cost numerical methodology is used to capture the influence of surface roughness in a subwavelength acoustic absorber. With this approach
the impact of roughness can be captured in the design process. The intention is to develop efficient low-cost design methodologies that can be exploited for industrial development of novel additively manufactured acoustic materials.
Aeroacoustic analysis of flow induced resonance in a gas pipeline
Authors: QUARANTA Erika , SMITH Malcolm , TAGGART Steven
Published: October 2024

Flow induced noise and vibration in the pipework of gas production platforms can lead to fatigue failures of attached small-bore pipes, and this can constrain the operating conditions of the platform. Typically such problems comprise a source of turbulence in the flow, an aeroacoustic
feedback mechanism due to acoustic resonances inside the pipework, and mechanical resonances which amplify the resulting vibration. The problem described here occurred in the gas metering system of the platform, with the source located in the header which comprised a bifurcation into two metering
lines and a number of sharp bends. Because of the cost of rectifying the problem an in-depth study was carried out to analyse the flow and induct acoustic conditions. The predictions will support recommendations for an efficient redesign of the entire system to control the problem at source.
Various levels of CFD modelling (RANS and URANS) were carried out using the Openfoam code to predict the exact location and mechanism of the vortex shedding. The acoustic response of the complex ductwork was then modelled using the ACTRAN code to understand the feedback mechanism which led
to resonance and high levels of response.
Innovative Strategies for designing acoustic encapsulations for e-motors to tackle NVH performance challenges
Authors: MISKIN Atul , HIMAKUNTLA Uma Mahesh , SHINDE Rahul
Published: October 2024

The automotive industry's rapid transition towards E-mobility is presenting novel challenges for NVH engineers having broadband frequency composition and tonal characteristics. The purpose of the paper is to present innovative strategies for electric motor NVH development by directly
applying acoustic encapsulation made of poro-elastic materials onto the casing of the electric motor. The first strategy is a pure simulation approach with combination of finite element analysis (FEA) and statistical energy analysis (SEA). Finite Element Analysis is used to calculate radiated
power of electric motor casing for Maxwell electromagnetic excitations on stator teeth. This radiated power is then applied as excitation on the SEA model of the electric motor casing for prediction of exterior noise using Statistical Energy Analysis. The second strategy is a hybrid approach
of simulations and experimental measurements. Electric motor is characterized as a source in terms sound power from experimental measurements of sound pressure as per ISO Standard: ISO 3745:2003. This power is applied as excitation in the interior of SEA model of the electric motor for prediction
of exterior noise. Both the strategies allow design of optimized sound package on the SEA model of electric motor using statistical energy analysis to achieve the NVH performance.
Characterization of the scattered pressure from a cylindrical shell close to a free surface and understanding of the depth-dependent phenomenon
Authors: PERIN Anaïs , LEON Fernand , CHATI Farid , MAXIT Laurent , MEYER Valentin , DUTTO Patrick
Published: October 2024

The characterization of the scattered pressure field of a submerged cylindrical target is of interest for underwater acoustics applications. The aim of this work is to study the vibroacoustic behavior of an immersed cylindrical shell excited by a plane wave, particularly in close proximity
to a free surface. To achieve this goad, finite element simulation and experimental investigation are carried out on a mock-up. The effect of the free surface is highlighted by comparing results to those obtained in a free field situation, in both time and frequency domains. Additional echoes
are observed on the time signals due to the presence of the free surface. In fact, after being scattered by the target, these echoes reflect on the surface, implying a time shift between echoes directly from the target and those that have travelled a longer path. The spectrum is also impacted
as the form function shows additional oscillations. These observations are depth-dependent. To determine wave trajectories, a study based on flight time and ray theory is conducted.
Rooftop pools - a problem from an acoustic point of view: how to identify and solve it
Authors: FENGLER Bárbara , ROCHA Raquel Rossatto , GINER José Carlos
Published: October 2024

There is no standard with specific methods for acoustic testing of rooftop swimming pools in Brazil. On the other hand, although the compatible requirement for impact noise from rooftop leisure environments is not the type of noise generated by swimming pools, it is a current requirement
in the Brazilian performance standard. To study the subject, evaluate possible solutions and improve the state of the art, this article brings measurement results for impact noise in the same situation without and with the application of an acoustic solution. The study also presents sound
pressure level and vibration measurements in an environment below a swimming pool after the application of the acoustic solution. Vibrations were measured as well in the pool structure and in the slab below, making it possible to identify the vibrational behavior of the pool. Measurements
of impact noise took place in a situation where the pool is three floors above the last residential unit to verify the influence of technical slabs. With the measured values in the three situations, it was possible to identify the frequency range for which acoustic solutions should be designed
for this type of source and to monitor the effectiveness of different solutions.
Sound transmission through an unbaffled plate
Authors: DIKSHIT Hemanta , SONTI Venkata R.
Published: October 2024

Commonly occurring complex structures can often be modelled as simple finite plates mounted without baffles. Thus, the objective here is to study the sound transmission loss of a simply-supported rectangular finite unbaffled plate impinged upon by an acoustic plane wave. The total pressure
jump across the plate surface is expressed as the sum of the pressure jump due to pure diffraction, where the plate normal displacement is zero and the pressure jump due to plate radiation. These pressure jumps are computed using the definition of the free-space Green's function in the wavenumber
domain and the Euler equation. Then, the coupled equation of motion is solved for the plate displacement. The method of stationary phase is used to derive the closed-form expression for the improper double integral that appears in the far-field acoustic pressure. Finally, the far-field transmitted
power is numerically computed and the sound transmission loss of the unbaffled plate is compared with that of the baffled one.
Investigation on supersonic jet noise reduction by water injection: Effects of water injection parameters
Authors: BELTRA Pierre , LALIZEL Gildas , GERVAIS Yves , DORIGNAC Eva , MOREAU Florian , BERTERRETCHE Patrick , BOUJU Romain , LAMBARÉ Hadrien
Published: October 2024

In order to protect the payload and the rocket structure from severe vibrations, water injection is commonly used on launch pads to reduce the high noise level radiated by supersonic plumes at lift-off. Even if this technique is widely used, the mechanisms behind sound reduction remain
unclear. Sound reduction occurs due to multiple phenomena, each of them having different effects on the jet noise. Experiments based on acoustic measurements have been carried out on a hot supersonic jet on MARTEL facility (Mach number of 3 and a total temperature of 1700 K) to deeper identify
the effect of evaporation and water injection parameters. Water flow rate, water injection speed and injection distance to the nozzle have been tested independently to identify the most important water injection parameters. It appears that water flow rate is the most important parameter to
decrease noise level and that injecting water at high speed results in noise increase in the downstream direction. Results also highlight the importance of having liquid droplets at the end of the potential core to reduce noise.
Studying infrasound propagation in the middle atmosphere with ICON and UA-ICON: comparison with the IFS and ground-based remote sensing
Authors: KRISTOFFERSEN Samuel , LISTOWSKI Constantino , WING Robin , BAUMGARTEN Gerd , KHAYKIN Sergey , HAUCHECORNE Alain , VERGOZ Julien , LE PICHON Alexis
Published: October 2024

Infrasound signals are used to monitor various anthropogenic and natural sources. In particular, infrasound is one of the four verification technologies used by the International Monitoring System (IMS) of the Comprehensive Test-Ban Treaty organisation (CTBTO). To determine accurate
source locations and energies, an accurate model of wind and temperature up to the lower thermosphere is necessary, hence operational NWP products are of great importance for routine infrasound monitoring activities. However, many of these models focus on tropospheric conditions, and the middle
atmosphere (MA) is not well represented. UA-ICON is an upper atmosphere version of the ICON model that provides modelled atmospheric parameters up to 150 km. First, to assess ICON and IFS operational analysis products, comparisons to lidar observations are made. The main differences between
both products were analysed with respect to winds and temperatures in the MA. Second, UA-ICON simulations outputs were compared to ICON and IFS fields to demonstrate the increased wave activity above ~30 km with UA-ICON. The added value of UA-ICON with respect to ICON and IFS for infrasound
propagation simulations is discussed. The comparisons between the instrumental observations and the models will be presented, as well as comparisons between modelled and measured infrasound propagation.
A comparison of results with different logging rates using ISO/PAS 1996-3:2022
Authors: MANVELL Douglas , KING Thom , WHITEMAN Michael
Published: October 2024

Noise with prominent impulsive sound is more annoying than continuous types of noise (without impulses) with the same equivalent sound pressure level. Therefore, an adjustment is added to the measured LAeq if prominent impulsive sound is present. In ISO 1996, three categories of impulsive
sound are defined, with adjustments for each. The list of sources of impulsive sound for each category is incomplete. ISO/PAS 1996-3 defines an objective method to measure the prominence of impulsive sound relative to residual sound. This can be used to categorize the impulsive sources, complementing
the ISO 1996-2 environmental noise assessment method. The method is based on logging LpAF with 10-25 ms time intervals. Short-term LAeq (e.g. 10 ms), although not preferred, can be used to compute these values. 100 ms sampling is permitted for surveys and screening. Annex A of ISO/PAS 1996-3
PAS encourages further research to support the development of a full ISO standard. This includes the application of real-world sources assessed at receiver locations including typical signal to residual noise ratios. This paper describes such a study under these conditions that investigates
the impact of the time intervals on results.
Analysis of the physical mechanisms responsible for the Acoustic Black Hole effect
Authors: GAUTIER Francois , BESSE Alex , AKLOUCHE Omar , ABLITZER Frédéric , PELAT Adrien
Published: October 2024

An acoustic black hole (ABH) inserted into a mechanical structure provides effective vibration damping without making the structure heavier. This property is particularly interesting in contexts where mass reduction is important. In practice, the ABH effect embedded in a beam or in
a plate results from the combination of a local reduction in thickness and the addition of a thin viscoelastic damping layer. Consequently, an ABH is a weak point in the structure, which leads to the existence of local modes. An ABH can be seen as a penetrable resonant scatterer, with a high
density of modes, all critically coupled. These properties intrinsically define the conditions required to obtain a true ABH effect. This definition will be presented and illustrated on examples of increasing complexity.
Acoustic road surface maintenance on low noise asphalts in Switzerland with grinding
Authors: SCHLATTER Felix , BALMER Tobias , BüHLMANN Erik
Published: October 2024

This study investigates the effectiveness of grinding techniques on special low-noise pavements as well as conventional asphalt surfaces in order to restore or enhance their noise-reducing properties. This study analyzes 17 different test tracks where grinding techniques were applied,
featuring various surface types and stages of aging. The research employs Close-Proximity-Measurements (CPX) and additional methods to evaluate surface characteristics. Initial results reveal significant acoustic improvements from grinding, especially on surfaces with 4- and 8-mm maximum aggregate
size. However, the durability of these measures varies, with 4~mm surfaces returning to baseline after 2-4 years, while 8 mm surfaces benefit for approximately 4 years. The study demonstrates that grinding methods can enhance acoustics through surface texture improvement and partially reactivating
previously clogged pore spaces. The effectiveness depends on the initial acoustic state and grinding depth, emphasizing the importance of setting clear objectives for optimal results. In summary, this study underscores the effectiveness of grinding in enhancing the acoustic quality of low-noise
road surfaces. Moreover, its integration into road surface maintenance strategies is a new tool for extending the functional and acoustic lifespan of low-noise road surfaces.
Modelling structure-borne sound and radiation of submerged structures at high frequencies
Authors: PALAMA Samuel , RICHTER Martin , TANNER Gregor , MEYER Valentin , CHEVILLOTTE Fabien
Published: October 2024

Predicting the vibroacoustic behaviour of structures in contact with water and at high frequencies can be a complex task due to the fluid-structure interaction. Computation time increases with frequency and the complexity of the structure. Being able to predict the sound radiated by
a naval vehicle in contact with water could help in improving passengers' comfort as well as the impact on the marine fauna. We use a prediction method called Dynamic Energy Analysis (DEA), so far emloyed mainly to assess the vibrational energy levels in the structure itself. DEA is a phase-space
based ray tracing method determining energy densities in terms of the ray densities in a structure. The method can be applied on FEM-meshes and thus needs no SEA type substructuring. We expand the DEA methodology here to take into account radiation into the fluid in contact with the structure.
From structure borne DEA calculations, we can determine directional sound radiation patterns both inside and outside the structure. We will demonstrate the new technique using some simple model systems.
Introducing uncertainties in acoustic engineering studies
Authors: RIPOLLES Jean , THéNINT Thibaud , SCHMICH YAMANE Isabelle
Published: October 2024

PIBE (Prévoir l'Impact du Bruit des Éoliennes - Predicting the impact of wind-turbine noise) is a research project funded by ANR (French National Research Agency) which main objectives are to better understand the sound level created by wind-turbines and assess noise-reduction
solutions. One topic of this project focuses on the propagation of uncertainties. Code_TYMPAN(tm) is an open-source software for calculating industrial noise in the environment. Its open architecture, implemented by a Python API, allows advanced users to build and solve models programmatically.
This open architecture made possible the implementation of a parametrical computational tool. This tool generates input data, launches the calculations with Code_TYMPAN(tm), generates and post-processes output data. Thus, sensitivity analysis and propagation of uncertainties were performed
on an industrial test case. This development demonstrates the feasibility of introducing uncertainties in acoustic engineering studies.
Infrasonic detection and monitoring of active tornadoes
Authors: WAXLER Roger , FRAZIER Garth , TALMADGE Carrick , LIANG Bin , BUCHANAN Hank , HETZER Claus
Published: October 2024

The notion that tornadoes emit an infrasonic signal that can be detected from great distances; and thus be used to aid in the detection, monitoring, and potential tracking of active tornadoes; has been discussed for decades. Much evidence has accumulated showing that tornadoes emit
acoustic radiation in at least two distinct frequency bands, an infrasonic band and a low frequency audible band. It is believed that the physical mechanisms responsible for the infrasonic and audible emissions are different. We will focus here on the infrasonic emissions. Experimental evidence
that tornadoes do indeed emit an infrasonic signal will be reviewed and the current status of the theoretical understanding of the radiation mechanism will be discussed. Data collected during the passage of storm fronts that did not spawn tornadoes were also analyzed to address the possibility
that the observed infrasonic signals might be associated with storm fronts rather than tornadoes. Those results will be presented. Finally, our current research campaign and plans will be outlined.
Designing noise barriers with additional purpose - five examples
Authors: FRIMAN Manne
Published: October 2024

Designing noise barriers with additional purpose gives more value to the built environment. Built examples are described in this paper with design process and resulting effect. The examples presented briefly below serve as inspiration on how to design barriers with additional purpose.
For an innovation contest, which required a sustainable solution, a 3D printed shot-earth barrier was designed that could be created from the soil in the surroundings. For a park where safety was required a low T-shaped brick barrier was designed to keep visibility into the park. For a planned
playground, next to a ferry advancement area, a barrier and a surround system with added jungle sounds was designed. In pursuit to increase barrier technical service life, an added device was designed to increase noise reducing effect and protection of the barrier. In another innovation contest
a combined solution for air quality and noise was required. The proposed solution was a sonic crystal made of a bioreactor algae farm and vegetation added on noise barrier. The examples are shown in this paper with description, test results and images.
Sound absorption coefficient in the audible and ultrasonic frequency range measured in a reverberation chamber with an omnidirectional parametric loudspeaker
Authors: ARNELA Marc , BURBANO-ESCOLà Ricardo , SCOCZYNSKI RIBEIRO Rodrigo , GUASCH Oriol
Published: October 2024

An omnidirectional parametric loudspeaker (OPL) is a sound source that contains hundreds of ultrasonic transducers set on the surface of a sphere. Each transducer emits an ultrasonic collimated beam consisting of an audible exponential sweep sine (ESS) modulated in amplitude. This results
in hundreds of ultrasonic sound waves emitted in all directions, but also audible sound waves generated by the parametric acoustic array (PAA) phenomenon, by which a modulated signal returns to the audible range thanks to nonlinear propagation in the air. This work examines how the OPL performs
in assessing room acoustics, specifically in determining material sound absorption coefficients within reverberation chambers. The ISO 354 standard requires measuring reverberation times with the chamber empty and with the material sample. These are measured using ESS, which has proven effective
for the OPL performance. This signal concentrates all the sound power into a single frequency, which improves ultrasonic power levels and thus the signal-to-noise ratio of the audible sound field. The absorption coefficient is next evaluated following the standard, and the results are compared
with those obtained using a standard dodecahedral loudspeaker. Finally, the absorption coefficient in the ultrasonic range is examined to evaluate the OPL performance in this frequency range.
Directional perception and its influence on noise annoyance from unmanned aerial vehicles
Authors: EVENSEN Karen Brastad , HAUGE Leo Heggem , GJESTLAND Truls
Published: October 2024

The use of Unmanned Aerial Vehicles, commonly known as drones, has seen a rapid increase in recent years and is projected to continue growing. As a result, drones have become a new source of environmental noise pollution, and the potential for annoyance reactions among the population
is likely to increase. The literature shows that the noise from drones is more annoying than noise from road traffic or aircraft due to its unique acoustic characteristics, such as pure tones and high-frequency broadband noise. However, it is possible that non-acoustic factors, such as the
listener's inability to locate the source, play a role in the perceived annoyance. This study aims to test and conclude whether this is a contributing factor to why drone noise is perceived as more annoying than other environmental noise sources.
Underwater acoustic target recognition based on multi-resolution wavelet feature deep learning
Authors: ZENG Mingmin , ZENG Xiangyang
Published: October 2024

The application of underwater acoustic target recognition is extensive, exploration of marine resources, submarine vehicle detection and so on. However, traditional feature extraction methods are susceptible to the influence of complex marine environments and target operating conditions,
leading to a significant reduction in the correct recognition rate. This paper introduces an underwater acoustic target recognition method that integrates multi-resolution wavelet features with deep learning algorithms, aiming to overcome the limitations of traditional time-frequency analysis
techniques, which are unable to extract multiple signal characteristics simultaneously due to the trade-off between time and frequency resolution. Specifically, the essence of this technique is twofold: (1) Selecting suitable wavelet bases and decomposition levels to capture signal characteristics
at different resolutions, effectively seizing the signal's local features within the time-frequency domain; (2) Fusing signal features across different resolutions to optimize the feature extraction process and enhance the distinguishability of target features. Finally, by applying deep learning
algorithms to experimentally measured underwater acoustic data, the results demonstrate that this method can effectively enhance the accuracy of underwater acoustic target recognition.
How to get high-rise residential design to respond road traffic noise
Authors: XU Zeyu , YU Lei , ZHANG Peng
Published: October 2024

Rapid urbanization causes acute contradictions of road traffic noise on residents' health. Although many works have been done in this field, specific investigations of how to get a design of residential area to correspond road traffic noise is still limited, especially in a high population
dense area. This paper, therefore, focused on high-rise residential blocks, researching relations between design variables and distribution of road traffic noise. In the study, a typical high population dense city, Shenzhen was employed as study case. Based on noise map simulation, design
element, block layout, design of individual buildings was proved important in traffic noise impact. The results discovered that the noise reduction effect is relatively significant when the building setback is within 30 - 40 meters of setback curb. To minimize traffic noise impact, flexible
layout of board point perimeter type might play an important role. Lowering building heights with increasing the number of building rows, two-story podiums around high-rise buildings, and the addition of balcony railing plate could result in significant noise reductions. Focusing on design
elements, this work developed an overall evaluation to improve acoustic environment of high-rise residentials based on noise map simulation, and provided significant contributions in responding road traffic noise.
Methodology for 3D sound synthesis of directional acoustic sources by higher-order ambisonics
Authors: THORNER Philippe , DOC Jean-Baptiste , LANGRENNE Christophe , BAVU Eric
Published: October 2024

This paper presents the 3D sound field synthesis using both the multimodal method and higher-order ambisonics (HOA) of the pressure field radiated by directional acoustic sources. Ambisonics is a technique for encoding and reproducing measured or modeled (virtual) sound pressure field,
based on a decomposition of the acoustic field over spherical harmonics. The directional source considered in this work is an acoustic horn excited by a flat piston. The free-field radiation from this horn is first modeled accurately over a wide frequency range using the multimodal method,
which requires relatively low computational resources. This radiated pressure field, collected on a dual-layer sphere of virtual sensors distributed over a Lebedev geometry, allows its projection into the ambisonic domain. The pressure field is then synthetized in the laboratory's 3D 5th order
HOA spatialization sphere, which consists of fifty-six loudspeakers. This offers the ability of listening to the radiated sound using a higher-order ambisonic synthesis of a 'virtual' source before it is manufactured. To qualitatively evaluate the performance of the proposed procedure, the
transfer function of the synthesized horn is measured around the listening point within the spatialization sphere. Key words : 3D sound synthesis, high-order ambisonics, directive sources, waveguides, horn, multimodal method
Simulation of pulse width modulation strategies: validation based on sound quality evaluations
Authors: WANTY Salomé , LE BESNERAIS Jean , PARIZET Etienne , TOTARO Nicolas
Published: October 2024

Though the noise emitted by an electrical machine is less loud than the one from a combustion engine, the existing literature shows it is not always more pleasant. This is because of its strong tonal content, due to deterministic excitations (e.g. electromagnetic slotting and switching
effects, mechanical gear mesh effects). The main source of magnetic noise is the radiation of the stator submitted to electromagnetic forces, which are harmonic by nature. Their highest frequency components are generated by the Pulse Width Modulation (PWM) technique designed to vary the supply
frequency and operating speed of the electric machine. Several PWM strategies exist, leading to specific harmonic spectra. A temporal simulation model has been developed to auralize the corresponding electromagnetic noise emitted by the machine, considering its mechanical and electrical parameters.
A testbench has been adapted to test the relevance of the model, both from an electrical and acoustic point of view. The simulation model and the testbench can be used to generate virtual and real sound stimuli to be assessed in a jury testing. The subjective evaluations allow to assess the
relevance of the auralization model, but also to identify the least annoying strategies.
Study on radial deviation amplitude of out-of-roundness of resilient wheel installed on a subway vehicle based on vehicle operation safety regulation
Authors: ZHONG Shuoqiao , ZHOU Xin , CUI Yuanhuai , SHENG Xiaozhen , ZHONG Shuoqiao
Published: October 2024

Following the extensive use of resilient wheels on trams, several subways in China have also started to pre-launch testing of resilient wheels, while it remains to be at a beginning stage, the wheel maintenance during its long-term service has become a great concern by subway operators
and wheel suppliers. An effort is presented in this paper, trying to provide an invaluable reference. Firstly, a metro vehicle-track dynamic system model fitted with the resilient wheels is built. Then, based on the operation safety index and current wheel re-profiling regulations, the influence
of wheel axial and radial stiffness combination on radial deviation maximum of resilient wheel polygonization wear is analyzed. The equivalent stiffnesses of the resilient wheel involve the radial stiffness within 600 kN/mm and the axial stiffness within 100 kN/mm. The amplitude of polygonization
below the 10th order on the resilient wheel is within 1 mm. A contour chart is drawn to present how the wheel weight reduction rate varies with wheel polygonization order and amplitude under different combinations of resilient wheel equivalent axial and radial stiffnesses. A series of contours
is abstracted to query the amplitude limits of the polygonization of different orders on resilient wheels with different equivalent stiffnesses.
The abjection of ultrasound
Authors: GRIMSHAW-AAGAARD Mark
Published: October 2024

The definitions of sound as found in the ANSI/ASA documentation (S1.1-2013) play an important role in the abjection of ultrasound. However, the threshold of ultrasound is a matter of debate as the enhanced abilities of some humans to sense ultrasound are now being discovered. While
definitions and standards are useful for enabling structures of knowledge, they also situate knowledge in power structures, leaving epistemological blind spots in their wake. Particularly within policy making on noise and health this may have palpable consequences in the future. My foci with
this paper are not only to map out how anthropocentric definitions of sound contribute to the abjection of ultrasound, but also to address some serious consequences for the human relationship to nature. First, I discuss definitions of sound and present examples of anthropogenic ultrasound
production in the environment. Then I survey research on the negative consequences for the environment of anthropogenic ultrasound production. Finally, I show how the abjection of ultrasound is a consequence of our definitions of sound and the accompanying situated knowledge. With tools like
resourcification theory and the concept of waste as scat, I then suggest ways in which anthropogenic ultrasound production can be encompassed in environmental impact debates.
Acoustic refurbishments in a university lecture room: effects on speaker's comfort and voice use
Authors: CANSU Nicole , ÖHLUND WISTBACKA Greta , HOLMQVIST-JäMSéN Sofia , RYDELL Roland , ARVIDSSON Emma , LYBERG ÅHLANDER Viveka
Published: October 2024

Poor acoustic conditions in learning spaces have a detrimental effect on the speaker´s health and constitutes a risk factor for voice disorders. Previous research indicate that an acoustic refurbishment of the learning space has the potential to increase well-being and decrease
voice related health problems among teachers, but the research is scarce. In this study, we aim to investigate how different acoustic conditions affect the speakers voice use and self-perceived speaker's comfort. Voice recordings of short speech-tasks and self-evaluations of speaker's comfort
were collected from fifteen participants during a three-step acoustic refurbishment of a real-life university lecture room in an experimental setting. The influence of background babble and a classroom soundfield amplification system on vocal parameters and self-perceived speaker's comfort
were also investigated. Factor analysis of the speaker's comfort questionnaire revealed a two-factor solution where factor 1 represented vocal behavior and perception of room acoustics, and factor 2 represented the perception of the task in itself. Sum scores for factors 1 and 2 will be calculated
and used in a mixed-effects model investigating the effect of room acoustics on self-perceived speaker's comfort.
Influence of randomly placed resonant aggregates on the attenuation properties of metaconcrete: A numerical study
Authors: TARTAGLIONE Fabiola , KOENKE Carsten
Published: October 2024

Concrete is a key material for many structural components in engineering, but its acoustic performance remains under discussion. Hence, the potential of the so-called metaconcrete has gained attention in research, mainly due to its capability to control vibrations and sound transmission
when resonant aggregates are embedded in the concrete. These resonant aggregates are designed to have resonant frequencies regarding frequency bands of interest, so the interaction with the incident sound waves is attenuated within those frequencies. While available research has focused on
the characterization of metaconcrete with a periodic arrangement of resonant aggregates, there is a gap regarding how their random allocation affects the characterization of metaconcrete. This study focuses on the numerical analysis of metaconcrete and the influence of randomly placed resonant
aggregates on its attenuation properties. The numerical approach concentrates on the aggregate's material composition, location and volume fraction within the concrete to identify configurations that exhibit great wave attenuation. The results have shown that the attenuation effect is substantially
advantageous when using a multi-frequency configuration for aggregates within the metaconcrete. Additionally, the random embedding of resonant aggregates offers a practical solution for their application in concrete structures.
The challenges of mapping quiet urban areas from mobile sound surveys
Authors: ALVARES-SANCHES Tatiana , OSBORNE Patrick , WHITE Paul
Published: October 2024

Detailed spatial data on noise levels are needed to identify quiet areas. Yet noise maps derived from sound propagation models based on traffic flows or sensor networks are often incomplete. Surveys using mobile sound recording coupled with machine learning modelling have offered a
possible solution, but so far have focused on averaged noise levels. We argue that quiet areas should ideally be consistently quiet, rather than simply quiet on average, yet mobile survey data usually lack the full temporal profile needed to quantify consistency in noise levels. Using data
from our Southampton study area, we show that modification of the loss function used in machine learning modelling of mobile survey data can yield information on the likely range of noise levels at any location across an entire city. We use this approach not only to identify locations that
are consistently quiet, but also to help understand which urban features may be associated with quiet, average and noisy events at any given location.
Vegetal wools for building application: investigation of optimization approaches for the enhancement of low-frequency sound absorption
Authors: MUTEL Lucien , PIéGAY Clément , GLé Philippe , GOURDON Emmanuel
Published: October 2024

Bio-based building materials, such as vegetal wools for thermal and acoustic applications, are increasingly used in construction. Indeed, as they store atmospheric carbon dioxide, they have a lower carbon footprint than conventional materials. Despite high-level multi-functional properties,
they suffer from poor low-frequency absorption for thin panels (less than 5 cm thick). Therefore, it seems relevant to investigate the optimization possibilities available, including meta-material approaches, and to adapt them to the specificities of vegetal wools, such as a low air resistivity
for hemp and flax wools which are our main concern. To meet this challenge, a state-of-the-art is being carried out to identify the optimization methods best suited to the specific characteristics of vegetal wools. This preliminary work is based on the implementation of an initial optimization
concept using a multilayer poroelastic material with a perforated resistive layer. The material structure is optimized using analytical modeling to target low frequencies. Experimental verifications are then carried out to determine the sound absorption coefficient of vegetal wools with optimized
configurations.
Noise sensitivity: a systematic review of available instruments
Authors: SONG Eunsung , ZIMMER Karin , MARQUIS-FAVRE Catherine , ELLERMEIER Wolfgang , PARK Sang Hee
Published: October 2024

The concept of noise sensitivity has been studied for more than 40 years now, but surprisingly, there has been no quantitative, meta-analytic, or systematic review of that domain. Routinely, noise sensitivity scales are used in psychology, engineering sciences and epidemiology, by using
different instruments, not always based on the same concept. Therefore, our aim is to systematically review the psychometric properties of these instruments used to assess noise sensitivity. First, we collected documents on noise sensitivity in four languages (English, French, German and Korean)
using specific search terms from 17 databases (PubMed, PsychINFO, Scopus, etc.), searching 13 conference proceedings (Internoise, Euronoise, ICBEN, etc.), and directly querying stakeholders (experts, federal ministries, etc.). After screening and categorizing the material, we assessed the
quality of the noise-sensitivity scales found using the COSMIN checklist, a standard to evaluate outcome measures. The goals of this systematic review are (1) to show in what research and applied contexts noise sensitivity is measured, (2) what instruments with proven psychometric quality
are currently available to measure it, and (3) how the usage of noise sensitivity scales differs between languages/cultures. [Registration of the systematic review: PROSPERO 2023 CRD42023440594. Research funded by "Fondation pour l'Audition", grant FPA RD-2022-6]
A sub-wavelength metamaterial layer for reducing underwater noise radiation of marine structures
Authors: BLANCHARD Torea , LECOQ Damien , LAGARRIGUE Clément
Published: October 2024

Reducing the underwater noise radiated by marine structures is a critical issue for improving submarine stealth or limiting the anthropogenic impact of commercial ships. In this study, we propose a lightweight passive solution based on a metamaterial to efficiently reduce the noise
at low frequency (< 1000 Hz) that can be transmitted through the shell plating of a marine vessel. This solution is made of a soft acoustically impervious poro-elastic foam in which inclusions are periodically positioned. Added to a plate, this metamaterial outperforms the mass law in the
sub-wavelength domain when separating two air domains. This performance is due to the periodic arrangement of inclusions in the foam, creating a vibro-acoustic bandgap. The aim of this study is therefore to assess this solution where the domain of the transmitted acoustic wave is water. Firstly,
numerical results on an unbounded plate are validated alongside the theoretical model of a flexible partition. When the metamaterial layer is added to the plate, it is shown that a vibro-acoustic bandgap still exists in the transmitted wavenumber domain, and that this solution is a good candidate
for achieving the objectives. Experimental measurements on a finite structure are then conducted and compared to numerical results
Global active noise control using SIMO near-field systems - Simulation and technical implementation
Authors: OSPEL Matthias Wolfram , NOLTE Niklas , WITTE Matthias , WURM Frank-Hendrik
Published: October 2024

The technical implementation of a single-input multiple-output (SIMO) active near-field noise control (ANC) system designed for global low-frequency noise control is presented. The SIMO control strategy is motivated by noise control simulations based on a direct boundary element method
(BEM) ansatz formulated in this paper. The suitability of the chosen BEM formulation and SIMO control strategy is accompanied and confirmed by extensive experiments and comparison to analytical calculations based on isotropic sources. The influence of parameters such as the positioning of
the error microphone, the membrane velocity required for optimal global reduction, the effects of phase inaccuracies and the number of actuators on global reduction are investigated. The real-time control of the SIMO system is technically implemented on field programmable gate array (FPGA)
hardware using a frequency domain block FxLMS algorithm. The iterative algorithm converges in less than 0.1 s for the examined frequency range from 100 Hz to 1000 Hz. Measurements using various circular SIMO array configurations showed reductions in sound power of up to 85\%, aligning closely
with the numerical results.
Numerical modeling of infrasounds radiation and propagation in hurricanes
Authors: VERDIER Antoine , SOCHALA Pierre , MARCHIANO Régis
Published: October 2024

Infrasound can be useful for monitoring natural or human-induced energetic events in the atmosphere. For high-energy sources, the infrasonic signals can propagate over large distances around the globe, given the low rate of atmospheric absorption. This study focuses on the numerical
simulation of infrasound propagation in realistic large-scale three-dimensional (3D) environments. More precisely, we are interested in the simulation of infrasound, called microbaroms, which are radiated from extreme weather conditions such as hurricanes. The simulation of hurricane-induced
microbaroms relies on three main components: i) a hurricane model describing the atmospheric wind and pressure fields, ii) a microbarom source model, and iii) an infrasound propagation model. 3D simulations have been performed on a rectangular mesh. Azimuthal deviation caused by the hurricane
and the stratified atmosphere can be seen in 3D. Further studies are needed to improve each model, and the correlation between them. The ultimate goal is to be able to simulate radiated infrasound propagation for any meteorological conditions.
DNN-based HRTF individualization for accurate spectral cues using a compact PRTF
Authors: KO Byeong-Yun , NAM Hyeonuk , MIN Deokki , PARK Yong-Hwa
Published: October 2024

Head-Related Transfer Function (HRTF) plays a critical role in how the auditory system perceives spatial information. The spectral cues embedded in HRTF are vital for accurately determining the elevation of sound sources. In existing approaches, deep neural networks (DNNs) have been
utilized to predict the magnitude spectra of HRTF from images of the pinna, typically employing the HRTF log-magnitude as the output during training. However, HRTF encompasses the acoustic characteristics of both the head and torso, exhibiting direction-dependent patterns that pose challenges
in reconstructing its spectral cues. To address this complexity, we propose an innovative method for HRTF individualization. Our model uses Pinna-Related Transfer Function (PRTF) as the output during training, which helps alleviate the impact of sound reflections from the head and torso in
the head-related impulse response (HRIR). Our experimental findings, based on an HRTF dataset, illustrate that our proposed model excels in reconstructing the first and second spectral cues. Furthermore, it outperforms previous deep learning models in terms of log spectral distortion (LSD).
Aerodynamic and acoustic evaluation of a cylinder covered by stretched grooved fabric near critical Reynolds numbers
Authors: LI XIANGRU , MAO JIAQI , CHEN WANGQIAO , ZHOU PENG , ZHANG XIN
Published: October 2024

This study investigates aerodynamic drag and acoustic noise generated from a circular cylinder by wrapping longitudinally grooved fabrics. The fabrics are stretched to different levels to explore their potential for flow and acoustic control near critical Reynolds numbers. To analyze
the fabrics' surface characteristics, 3D scanning and several microscopic techniques were employed. The parallel-mounted load cells and an array of microphones were used to measure the drag and noise at Reynolds numbers, based on cylinder diameter, ranging from \num{3.3e4} to \num{1.1e5} in
an anechoic wind tunnel. Additionally, hotwire anemometry was used to examine the wake structures in the vicinity of the cylinder. The surface scanning results revealed that stretching the fabric transversely to twice its original size reduced the groove depth by approximately $54\%$
and increased the width by around $25\%$, resulting in an overall reduction of the arithmetic surface roughness $S_a$ by $18.6\%$. Based on the wind tunnel data, it was observed that a grooved fabric with higher stretch, and thus lower surface roughness
exhibited a minimum drag coefficient at a higher Reynolds number, along with reduced acoustic tonal noise levels.