bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of internal resonance on the nonlinear acoustic radiation induced by axial and bending vibration of hyperelastic cantilever beams
Authors: Wang Guoxu , Li Yapeng , Qu Yegao
Published: December 2023

This paper provides a numerical nonlinear vibro-acoustic study of a slender hyperelastic cantilever beam with 2:1 internal resonance condition. The model of beam includes geometric and material nonlinearities, while the model of acoustics includes the Arbitrary Lagrangian-Eulerian frame
and the perfectly matched layers. The finite element method and the time integration method are used to discretize the structure and acoustic field. A loosely coupled serially staggered procedure is used to compute the variable values of structure and acoustic field. The results show that
the transition from the axial mode to the bending mode of beam can be excited by the axial mode excitation. This leads to the alteration of acoustic directivity pattern and frequency components. Besides, due to the weak or strong coupling effects of axial and bending modes of beam, the symmetric
or asymmetric acoustic directivity patterns can be witnessed in different frequency components.
Preliminary study of Acoustic Black Holes implemented in CT/MRI housings including validation experiments
Authors: Thoma Niklas , Duvigneau Fabian , Juhre Daniel , Woschke Elmar
Published: December 2023

An increasing number of interventional use of computer tomograph (CT) scanners and magnetic resonance tomographs (MRI) leads to the need for particularly quiet medical imaging in order to minimize the stress level for patients as well as medical staff. Due to the many different imaging
sequences, noise reduction measures have to consider a wide range of different frequencies. Especially the use of Acoustic Black Holes (ABHs) seems to be a promising strategy to reduce vibration-induced noise. The objective of this study is to extend conventional measures for minimizing structural
vibrations, usually realized by applying composite stiffeners, by adding ABHs directly into these stiffening components. This allows vibration maxima to be minimised efficiently. In the first step, the vibroacoustic properties of composite materials are investigated numerically and the created
simulation model is validated by experiments. Based on these results, the influence of stiffeners on the structural behaviour is investigated and an optimised design for minimum surface velocities is found. To further reduce surface velocities in the frequency range where the human ear is
particularly sensitive, ABHs are tested. In this context it is investigated whether ABHs can be advantageously combined with conventional stiffeners. Keywords: Medical devices, Acoustic black holes, Noise and vibration
Experimental and numerical investigations on the dynamic response of a power transformer
Authors: Sahu Kiran , Daneryd Anders
Published: December 2023

In the manufacturing unit, there is a need of an accurate and reliable numerical tool to predict noise radiation from transformer. The first step to achieve this is to have a proper modal analysis of the active part (winding+core+clamping system). An impact test was performed on a 30
MVA power transformer unit and resonance peaks were identified from the FFT plots. Also, Operational Deflection Shapes (ODS) were extracted to visualize the displacement pattern of the test object. Moreover, the transformer unit was electrically energized, and vibration levels were measured
with Polytec 3D scanning laser vibrometer. A detailed numerical model was developed in COMSOL Multiphysics, and very good agreement was seen between the numerical and measurement results.
Comparison of microphone array techniques and standardized methods for sound power estimation
Authors: Takai Marjorie , Song Wookeun
Published: December 2023

The sound power level can be estimated using several well-established techniques available in the market. However, the variety of methods can be overwhelming when choosing among them due to environmental restrictions, standard requirements, and the necessary expertise to acquire valid
data. In this study, we aim to compare the results obtained with different techniques, either standardized, as described in ISO 3744 in hemi anechoic rooms and ISO 9614-1, engineering method, using sound intensity, and non-standardized microphone array methods, as optimized acoustic beamforming
and acoustic holography algorithms. The sound power levels of an omnidirectional sound source with pink noise as input and a printer were measured in a hemi-anechoic chamber using all the techniques. In addition, the measurement with the omnidirectional sound source were carried in a meeting
room to check the effect of room and background noise. Considering the results of the sound intensity method as the baseline, all the overall sound power level results varied within the uncertainty stipulated by ISO 9614-1 for both sources. The results in one-third octave bands were within
the uncertainty for all bands except one case for both sources in the case of refined beamforming.
A coupling FEM/BEM method for acoustic-structural interaction problems in uniform relative motion between structure source and fluid
Authors: Sun Ruihua , Wu Haijun , Li Jinxiao , Zhao Haiyang , Chen Bao
Published: December 2023

When a vibrating thin structure moves in a heavy flow field, the effect of sound waves on the structure cannot be ignored. This effect is especially pronounced when the relative velocity of the structure and the flow field increases. The hybrid numerical method of finite element method
(FEM) and convective boundary element method (BEM) is proposed to solve acoustic-structural interaction problems in uniform relative motion between structure source and fluid. Besides, an acoustic-analogy Lorentz transform is proposed to handle the direct convective boundary integral equation
(BIE), which makes the convective BIE has the same form as traditional BIE so that there are no more convective terms and extra singular integrals. The continuity condition at the fluid-structure interface is also proposed to generate the coupling equation. Compared with the traditional FEM,
this hybrid method has the advantages of greatly reducing the number of finite elements outside the structure as well as automatically satisfying the radiation condition at far field. And compared with the direct convective BIE, this method reduces the computational complexity and time. It
is potential to deliver a solver with higher accuracy and less memory consumption. Some numerical examples are designed to study the influence of the convective effect. Keywords: Acoustic-structural interaction, Finite element method, Boundary element method, FEM-BEM coupling
Comparison of measurement methods of room sound energy for sound insulation performance evaluation at low frequencies
Authors: Aida Yu , Sugie Satoshi , Takebayashi Kenichi , Tomiku Reiji
Published: December 2023

In the field measurement of acoustic performances, such as sound insulation and floor impact sound insulation, sound pressure level is usually measured to find the sound energy in a closed space. However, the sound pressure level at low frequencies such as the 63 Hz band depends on
the measurement position due to the influence of the room eigenmodes, which leads to large uncertainties of the measured average sound pressure levels in rooms. In this study, several measurement methods of sound energy were applied to the low-frequency sound field of a mock-up room that simulates
a source room in an RC apartment. Along with the standard sound pressure level measurement, the low-frequency procedure according to ISO 16283 series and acoustic energy density measurement using the combined particle velocity-pressure sensor were conducted, and their accuracies were evaluated
based on the average sound pressure obtained by the grid-point measurement over the entire room.
Determination of the characteristic impedance and the complex wave number by five different approaches
Authors: ZHAO Yujun , XU Jinhui , DAVY John Laurence , LIU Zhengqing , FARD Mohammad
Published: December 2023

This study presents several methods to determine the characteristic impedance and the complex wave number of porous materials. These methods include the two-cavity method by Utsuno et al., the two-thickness method by Dunn and Davern, the four-microphone transfer-matrix method by Song
and Bolton, the empirical method by Miki and theoretical calculation by the inverse method of Johnson-Champoux-Allard (JCA) model. Glass wool and polyester materials are used to compare different approaches. The results indicate a clear correlation among all methods. The theoretical calculation
based on the inverse method of the JCA model can predict well without direct measurement of the non-acoustical parameters. However, there are disadvantages to several methods including sharp peaks in some frequency ranges for the two-cavity method, data fluctuation at low frequency for the
four-microphone method, and inaccuracy in predicting the characteristic impedance of thick materials at middle and high frequencies for the two-thickness method. The results imply that the inverse method of the JCA model is a reliable method to predict the characteristic impedance and the
complex wave number with comparable accuracy to traditional experimental methods.
Lavor-saving input power identification method in actual operation using experimental SEA
Authors: OKAMOTO Ryota , YAMAZAKI Toru , KURIHARA Kai , KITAHARA Atsushi
Published: December 2023

Input power identification using experimental SEA requires measurement of all subsystems. However, it is sometimes difficult to measure the energies in operation in real mechanical structures. Therefore, this paper proposes a method to identify the input power during operation using
only the measurable subsystem energy, excluding the subsystem energy that is difficult to measure. This method is referred to as the "lavor-saving method". This method focuses on subsystems with zero input power. This method allows the input power to be identified even if the number
of subsystems whose energy is measured is reduced. This paper discusses the effect of the accuracy of the SEA model and its applicability, including the choice of measurement subsystems. The results show that to ensure the accuracy of input power identification in the lavor-saving method,
it is necessary to measure the input subsystem to be evaluated. Finally, the results of the application of the method to the identification of the input power from the road surface to the tire in rolling tests are reported.
Numerical investigation of tire shape parameters on the tire acoustic cavity resonance noise
Authors: Bao Yue , Liu Xiandong , Hu Xueman , Shan Yingchun , He Tian
Published: December 2023

Tire acoustic cavity resonance (TACR) noise is one kind of low-frequency and narrowband noise that particularly annoys the passengers, especially beyond endurance in the electric vehicles. This paper demonstrates a numerical investigation on the TACR noise via the acoustic-structural
coupling finite element model. According to the simulated models, shape parameters of inner tire cavity have been studied in detail, including the curvature radius of tire crown region ρ2, transition region ρ3, tire shoulder ρ4, and tire sidewall ρ5, together with the half-section
height H of the inner tire cavity. By the orthogonal test and range analysis, it is found that the curvature radius of the tire shoulder ρ4, tire sidewall ρ5, and half-section height H have a more obvious influence on the TACR noise, rather than the curvature radius of tire crown region
ρ2 and transition region ρ3. Meanwhile, it also illustrates that increasing the curvature radius at the tire shoulder ρ4 and reducing the half-section height H have a reduction effect on the TACR noise. This study can contribute to the design of low road noise tire.
Basic study of practical prediction of sound insulation performance of double-glazed window
Authors: Tsukamoto Yohei , Tamai Kaoru , Sakagami Kimihiro , Okuzono Takeshi
Published: December 2023

Since double-glazed glasses have superior thermal insulation performance compared to single-glazed glasses, they are widely employed for windows in recent buildings. However, the double-glazed glasses used in general buildings have mass-air-mass resonance at around 200-400 Hz, and,
at those frequencies, their sound reduction indices are often lower than that of single-glazed glasses that have the same weight. In designing an indoor acoustic environment, it is helpful to have a practical method to predict the sound reduction index of a double-glazed glass window, including
the resonance. In this study, at first, measured values of actual double-glazed windows are compared with calculated values of the existing sound transmission theories for double plates and applicability of the theories to double-glazed windows are investigated. Next, in order to obtain a
practical prediction of the sound reduction indices of double-glazed windows, some measured values of double-glazed windows are collected from a manufacturer's database and the characteristics of the sound reduction indices are discussed.
Evaluation of vibro-acoustic properties and structures of automotive door materials
Authors: Hu Yue , Sasajima Manabu , Kano Shuji
Published: December 2023

This study aimed to solve the challenge of reducing the weight of vehicles to improve their cruising distance while also suppressing noise intrusion and vibration generation. The intrusion of external engine and road noise, as well as the vibration of loudspeakers causing noise, were
the primary problems addressed. Our proposed solution involves exploring the use of multiple materials in automobile doors to determine a structure that maximizes material characteristics while maintaining acoustic performance. Specifically, our study focused on evaluating the vibration and
acoustic performance of various materials and examining the effects of different structural designs to achieve a lightweight and noise-resistant design.
Active Noise Control for Kitchen Hood
Authors: Regala Julia , Chang Cheng-Yuan , Mei Mu-Chun
Published: December 2023

A kitchen hood is an appliance that is powered by a fan motor to suck the exhaust in the kitchen while cooking. When turned on, it produces low-frequency noise that cannot be reduced by only a passive material. There is a direct relationship between the speed settings in the hood and
in the amount of noise that is produced. The higher the speed setting, the higher the noise. This broadband noise is reduced using the filtered-x least mean square (FXLMS) method with a feedforward active noise control (ANC) structure. To ensure a good reduction, the microphones must have
good coherence and must not be affected by the turbulent wind. The whole ANC system will use one reference microphone, several error microphones connected as one, and two anti-noise speakers connected as one.
Convergence of Noise, Climate, Air and Energy actions for an efficient planning: how to act on urban and architectural forms?
Authors: Strauss Philippe
Published: December 2023

While the nature of road traffic and weather conditions remain the main determinants of air pollution and noise in cities, urban design and architectural forms are parameters that planners can play with to combine protection against noise, adaptation to climate change, air quality and
energy management. But optimizing urban and architectural forms is not an easy task, because multiple factors are at work, particularly three-dimensional ones, which are sometimes contradictory. Orientation and height of buildings, continuity (or discontinuity) of the built front, layout and
distance of buildings from the source of nuisance, urban vegetation, internal design of housing and architectural details, are all levers that can be used to reduce the impacts on the resident population. In order to establish a hierarchy between the different problems, we propose a structuring
method to help objectify the priorities. It consists, for each of these influential parameters, in making an inventory of the potential gains and the points of vigilance with regard to noise, air pollution, urban overheating and energy savings and sufficiency. A number of French cities, including
the city of Bordeaux, have experimented this approach to plan development projects for highly environmentally ambitious neighborhoods.
An efficient hybrid aeroacoustic method to predict the noise of a ducted coaxial-rotor UAV
Authors: Zhao Zhiheng , Chen Weijie , Yang Cheng
Published: December 2023

Ducted coaxial-rotor UAV is a new concept UAV configuration. Compared with the traditional open rotor UAV, it has the advantages of higher safety, lower noise and smaller size, especially suitable for compact space and low noise scene applications. However, the complexity of the internal
flow field caused by the presence of the duct makes it difficult to obtain accurate acoustic results by using the conventional aeroacoustic simulation methods. Based on the theory of duct acoustics and the theory of propeller noise, this paper presents an efficient calculation method of aeroacoustic
source suitable for the configuration of a ducted UAV. The aeroacoustic source of a ducted coaxial-rotor UAV independently developed by the current research group is studied, and the duct acoustic mode components excited by the aeroacoustic source of the UAV are obtained. The results show
that the distribution of the duct mode excited by the aeroacoustic source of the ducted UAV has a strong correlation with the number of propeller blades, and the main characteristic modes dominate the acoustic source of the UAV.
Factors influencing the results of a social survey
Authors: Gjestland Truls
Published: December 2023

Social surveys are conducted to determine how annoyed people are in a certain noise situation. The results are typically presented as exposure-response curves showing the percentage highly annoyed as a function of the noise exposure level. A re-analysis of previously conducted surveys
reveal that the result is highly dependent not only on the noise level itself but also on a number of other factors like how the survey was conducted, how the annoyance questions were phrased, what kind of response scales were used, how was high annoyance defined etc. The influence of different
factors will be discussed and quantified.
The potential for spatiotemporal population data sets for aviation noise studies
Authors: Murphy Charles M. , Augustine Stephen , Warren Donna G.
Published: December 2023

Aviation noise analysis has traditionally focused on modeling the noise from an average day of operations. We investigate the potential of moving from this static approach to a dynamic method of assessing aircraft noise experienced by people where they are as they move about the day
and night. In this research conducted on behalf of the National Academy of Sciences Airport Cooperative Research Program, we evaluated population data sets that account for the movement of people between their daytime versus nighttime location and assessed their applicability for aviation
noise studies. We provided guidance on using these spatiotemporal data sets for aviation noise studies using the Aviation Environmental Design Tool, including sample maps and analyses. We also discussed the limitations of spatiotemporal population data, namely they only account for a person's
location by time of day and not whether they are engaged in noise-sensitive activities. A fuller picture of noise impact by location and time of day may be achieved by developing an activity-based model, which combines data on location and level of noise sensitivity. We outline the basic elements
of such a model.
Effect of embankment slope on road traffic noise propagation: numerical investigation and construction of correction formula for difference by slope angle
Authors: Yasuda Yosuke , Nishimura Seiya , Kamiya Yu , Morinaga Makoto
Published: December 2023

The propagation characteristics of road traffic noise from an embankment road are investigated through three-dimensional wave-based numerical analysis. Since this is a large-scale problem, we use the fast multipole boundary element method (FMBEM) as a highly efficient wave-based numerical
method. We analyze sound fields around embankments with various slope angles and clarify that the sound pressure gradient changes with the slope angle, and in particular, the sound pressure level (SPL) distribution changes significantly near the line where the embankment slope meets the ground
surface. When the prediction plane is an orthogonal cross-section to the direction of the lane, the distribution of the difference in A-weighted SPL between the case where the embankment is sloped and the case where it has a right angle is generally similar regardless of the position of the
prediction plane. Based on this result, we propose an empirical formula to express the difference between the case with a slope and the case with a right angle. We confirm that the proposed formula provides a certain level of accuracy regardless of the location of the prediction plane when
we appropriately determine the coefficients in the formula for each case from the viewpoint of error minimization.
Developing the algorithm for aircraft noise prediction on building façade
Authors: Ang Linus Yinn Leng , Chiang Kenny Jun Wei , Cui Fangsen , Poh Hee Joo
Published: December 2023

Although the COVID-19 pandemic has now become an endemic, working remotely for certain days of the week remains adopted in many companies as the norm. As the air traffic is heavier during office hours, residents staying near to an airport may suffer the adverse effects of aircraft noise
exposure relating to productivity and health. As this problem is present in many cities, aircraft noise prediction is important in aiding urban planning processes to identify and manage the problem accordingly. This paper presents our recent work on adding a new feature-important for interior
acoustic comfort evaluation-to predict aircraft noise on building façade. The computational procedure involves processing the façade geometry from the 3D model, determining the line of sight between the façade and the aircraft, and generating the noise map. Eventually,
this new feature will be integrated to a unified urban environmental modelling tool for the design of highly liveable and sustainable residential towns.
Sound propagation from the underfloor of railway vehicles to the wayside
Authors: Akiyama Satoru , Yamada Joji
Published: December 2023

It is important to consider the layout of underfloor equipment to make sure the train keeps low-noise under stationary condition. The arrangement of the underfloor equipment is important in view of not only the noise but also weight balance, maintainability and manufacturing cost. Therefore,
the underfloor arrangement shall be decided at even the early stage for designing the vehicles. The early design includes the exterior noise prediction as one of the important specifications. In general, there are various-size equipment, ducts and pipes, kinds of sub-floor made of thin metal
plates around the space of the underfloor. When the train is on ballasted track, both surfaces (ballast of the track / underfloor of the vehicle with ducts and piping) may have absorption effect but it is still unknown. This paper describes measurement results on the sound propagation from
actual railway vehicle underfloor using dodecahedral speaker.
Measurement of radiated sound directivity of moving sources at low Mach numbers
Authors: Makino Yusuke , Takano Yasushi , Akutsu Mariko , Uda Toki
Published: December 2023

It is well known that frequency and amplitude modulation occur when sound sources move. However, there are few studies on the effect of the sound source movement on its directivity. We performed an experiment using a scaled train model moving at low Mach number between 110 and 290 km/h,
with an ultrasound speaker. We then estimated the directivities of radiated sound from the source by measurements using a stationary microphone. We also calculated simulated directivities theoretically as a combination of source term and motion term. Thus, we compared the measured and simulated
directivities. As a result, it was confirmed that the two kinds of directivities were in good agreement.
Development of sound field simulation and optimization over large acoustic space by use of novel SEA method
Authors: Miyamoto Yasunori , Fujimoto Keisuke , Koido Teppei , Charpentier Arnaud
Published: December 2023

Panasonic is committed to providing customers with optimal PA system. The ability to predict PA system performance from digital mock-up is key to help designing optimal system under various conditions. Sound predictions over large spaces are challenging with FEM/BEM methods due to high
computational cost and response sensitivity. Additionally, adding detail in source or boundary is difficult with Ray-tracing methods. Finally, traditional SEA methods don't provide sufficient resolution of response. We have investigated a novel SEA method with ability to predict spatial variations
in acoustic response. Sound propagation in large public spaces over the full audio range was predicted, accounting for detailed loudspeaker source characteristics, room geometry and boundaries absorption. Predictions were validated against test in a Panasonic auditorium. Method was then used
to predict PA system performance in public space under realistic noise conditions. Inverse method was used to synthesize background noise source from limited test data. STI predictions were then performed and optimization carried out to identify PA system loudness requirements in order to
achieve best STI performance over wide area while minimizing signal loudness at any position for various background noise conditions.
Development of stealth design systems for advanced submarine hull forms to reduce underwater radiated noise and target strength
Authors: Hong Suk-Yoon , Song Jee-Hun , Yeo Sang-Jae
Published: December 2023

The stealth capability of a submarine is the key performance to be considered in submarine design since it is directly related to survivability and operational capability. In this study, a system that can be applied from the conceptual design stage for the submarine shape, including
the hull forms and appendages, has been developed by considering the two key components that determine the stealth capability of underwater vessels: underwater radiated noise (URN) and target strength (TS). First, for submarine stealth design considering URN, a design optimization technique
was developed that can reduce the high flow noise caused by the interaction between the propeller and the vortex generated in various parts of the hull and appendages. And for submarine stealth design considering TS, shape design technology that can minimize the reflections of active sonar
was developed through an evaluation method with high adaptability to shape modifications. Finally, by developing the optimization design procedures that comprehensively cover URN and TS, the optimal shapes and arrangements of sail and rudders that can maximize stealth performance have been
derived.
Proposal of reverberation time to match the visual aspect of the architectural space displayed in VR using panoramic photographs
Authors: Ishikawa Ayumi , Aoki Tetsu
Published: December 2023

Most VR applications in the field of architecture are based on visual information only, and the addition of auditory information is expected to provide a more realistic representation. In order to provide a comfortable VR experience, discomfort due to inconsistencies between visual
and auditory information should not occur. The aim of this study is to propose a reverberation time that matches the visual aspect of the architectural space displayed in VR using panoramic photographs. Subjective experiments were conducted on 15 virtual spaces created from panoramic photographs
of architectural spaces to determine a reverberation time that matches the visual aspect of these spaces and to subjectively evaluate the visual impressions. Based on the results, several models of reverberation time to match the visual aspect of the architectural space displayed in VR using
panoramic photographs were created. The results of this experiment showed that the model using the volume of the virtual spaces was appropriate.
Comparative Analysis of the Acoustic Performances of Modular and Ordinary Classrooms
Authors: LEE Jakin , LEE Seung-Min , HAAN Chan-Hoon
Published: December 2023

Since 2016, modular construction system was introduced to Korean school buildings as it gave both of benefits in time and economical gain. Though the modular school buildings are temporarily employed during the period while students were rapidly increasing due to the regional developments,
government has a responsibility to maintain the building performance for the education purposes. The purpose of this study is to investigate the classroom acoustic performance of modular school buildings. To this end, room acoustic parameters were measured in classrooms in four modular school
buildings. In addition, acoustic parameters including standardized sound insulation levels were measured to analyze the sound insulation performance of walls and floor impact noise performance. At the same time, equivalent acoustic parameters were measured in normal school classrooms for comparative
analysis. As a result, it was found that background noise levels of each classroom are satisfactory with the standard of 35 dB(A). Concerning room acoustic performance, modular classrooms were found to have better values than ordinary classrooms. Als, as for the sound insulation of walls and
floor, it was found that modular classrooms have better sound insulation performance than the ordinary classrooms beyond the general expectations.
Investigation of the Proper Sound Levels of Artificial Masking Sounds for the Speech Privacy in Open-Plan Offices
Authors: Lee Seung-Min , Haan Chan-Hoon
Published: December 2023

The present study aims to investigate the optimum level of masking sounds which can satisfy with both the occupants and acoustical privacy. In order to this, prior investigation was accomplished to know real condition of open-plan offices using questionnaire survey to 115 people. Also,
acoustic listening experiments were done to 30 people with 5 scale point questionnaire. Recorded voice was played with the output sound level of 57 dB at 1m from the directional speaker. Artificial making sounds were also radiated from the ceiling speakers using pink noise. Making sounds used
in the experiments consisted of 5 different sound levels which have SNR of 10, 13, 16, 19 and 22 dB. Using questionnaire, three responses from occupants were received including speech intelligibility, annoyance of masking sounds, and overall unpleasantness. As a result, it was found that SNR
22 is appropriate for the decrease of annoyance of masking sounds and overall unpleasantness while SNR 16 to SNR 19 is considered to be suitable for the reduction of speech intelligibility and the annoyance of masking sounds.
An experimental study on evolution of vortex structures in perforated cavity structures driven by acoustic waves
Authors: Tang Yuchao , Wang Peng , Liu Yingzheng
Published: December 2023

In the present study, the vortex dynamics in three perforated cavity structures with different gap distances (l/d = 2, 4, 6) subjected to acoustic waves is investigated by particle image velocimetry (PIV) experiments. First, using a data-acquisition at 48 kHz and transfer function method,
the incident acoustic waves of three perforated cavity structures at different frequency was examined. The relationship between the gap distances and the acoustic-vortex coupling phenomena was obtained. Then, PIV was carried out to obtain the flow fields and vortex evolution process in three
perforated cavity resonators at specific frequency. Comparisons of different gap distances showed that the vortices generated by turbulent entrainment are confined at the corner in the small gap distances (l/d = 2, 4). For larger gap distance (l/d = 6), large-scale vortices occur due to the
wall jet flow. Finally, the flow fields were analyzed by turbulent kinetic energy to obtain the dominant energy distribution and illustrate the energy conversion process.
Development of sound-absorbing materials from rice straw
Authors: Lawanwadeekul Siwat , Daothong Suphaporn , Sangkas Teerawat , Kongthavorn Panisara
Published: December 2023

This paper primarily studies the potential of using agricultural waste, specifically rice straw, as a sustainable material for sound absorption in interior spaces. The acoustic properties of rice straw were characterized and compared to traditional sound-absorbing materials. Rice straw
was found to have a high sound absorption coefficient in the mid-frequency range. The material was also environmentally friendly, as it is an agricultural waste product and can be easily replenished. This study does not need to use chemicals. Thus, the recycled paper was used as the binder.
The results of this study indicate that rice straw mixed with recycled paper can be a cost-effective and sustainable alternative to traditional sound-absorbing materials.
An effective hybrid deep neural network for underwater acoustic target recognition
Authors: Jin Anqi , Zeng Xiangyang , Lei Menghui
Published: December 2023

Underwater acoustic target recognition is an important support technology for underwater information detection and signal processing. Due to the high complexity of the marine environment, it is not easy to obtain clear and reliable features from ship-radiated noise, which makes underwater
acoustic target recognition difficult. We propose a new hybrid network of transformer networks and convolutional neural networks to alleviate this problem. It consists of three convolution modules and a transformer module. The convolution modules are used to learn the local features of the
time-frequency map, and the features are enhanced using the residual structure and channel attention. The transformer module is used to extract the global features of the time-frequency map. The proposed network can obtain global and local features of the ship-radiated noise from the time-frequency
map of the raw data, which can improve the accuracy of recognition. Experiments were conducted on DeepShip, a public benchmark dataset of ship-radiated noise, and compared with the current state-of-the-art methods. The results show that the proposed hybrid network achieves the highest recognition
accuracy on the DeepShip dataset.
Performance evaluation of sound source localisation and tracking methods using multiple drones
Authors: Yen Benjamin , Yamada Taiki , Itoyama Katsutoshi , Nakadai Kazuhiro
Published: December 2023

This study evaluates methods to improve sound source localisation and tracking performance using microphone arrays from multiple drones. Previous studies have demonstrated the feasibility of multi-drone sound source tracking by triangulating their respective direction estimations using
the MUltiple SIgnal Classification (MUSIC) algorithm. In addition, we evaluate techniques to reduce the influence of rotor noise. Namely, this includes a Wiener filter that utilises rotor noises' power spectral density (PSD) estimations and a noise correlation matrix (NCM) estimation scheme
exploiting the geometries of the drone and the microphone array. This is to reduce the rotor noise's influence on the microphone array input correlation matrix prior to localising with MUSIC. Results show that applying the rotor noise reduction method improves localisation and tracking accuracy
under a wider range of signal-to-noise ratios, regardless of the sound source tracking method.
Sound insulation design of vehicle side window glass based on acoustic black holes
Authors: WU Xian , LIU Mingyang , ZHU Zhiwei , QIN Shengjie , SHAO Jianwang
Published: December 2023

Acoustic black holes (ABHs) can reduce the mechanical vibration and radiated sound of a structure while simultaneously reducing its mass. By considering the practical application, a new vehicle side window glass is designed using ABH array to optimize its sound insulation performance
in this paper. The finite element method (FEM) is used to analyze the response and modes of the glass to validate its ABH effect. The accuracy of the Finite Element-Stational Energy Analysis (FE-SEA) model is verified using Gaussian expansion method (GEM) and Statistical modal Energy distribution
Analysis (SmEdA). Using the verified FE-SEA, the transmission loss (TL) of the new side window glass and the influence of the number of ABH layers are analyzed. It is observed that the overall TL of the new glass is better than that of the traditional one, which can highly improve the TL at
the coincidence frequency and meanwhile reduce the weight. It provides a new technique to design vehicle glass to improve vehicle sound insulation performance.
A comparison of subjective responses to simultaneous traffic-induced vibration and noise in buildings between Japanese and Vietnamese participants
Authors: Tung Nguyen Thanh , Matsumoto Yasunao , Morihara Takashi , Yokoshima Shigenori , Hayashi Kentaro
Published: December 2023

Vibration and noise are the major environmental problems and the main causes of many adverse effects on the living environment. Up to now, only a few studies have compared the subjective responses due to simultaneous vibration and noise in buildings induced by traffic between two different
national participants. This paper investigated the subjective responses to simultaneous vibration and noise with two groups of participants: Japanese and Vietnamese who were studying in Japan. They were exposed to 31 stimuli consisting of six levels of noise and five magnitudes of vibration
from conventional and high-speed Shinkansen railways, and road traffic. They were asked to rate their levels of discomfort on a seven-ordinal scale. Finally, the difference between the two groups of participants in subjective responses to combined exposures was shown.
Prediction of room acoustic parameters in rectangular rooms using recurrent neural networks
Authors: Huszty Csaba , Bakos Bence , Csanády Bálint , Hidy Gábor , Lukács András
Published: December 2023

Reliably and efficiently predicting room acoustic parameters in rectangular rooms with an uneven distribution of materials and sound absorption is a common task in room acoustic design. Readily available statistical formulas are often not applicable to typical classrooms, cellular offices,
or hospital wards. Furthermore, many of these methods only predict the reverberation time, each with their own, often ambiguous limitations of applicability which is impractical for an efficient room acoustic design process. On the other hand, predicting room acoustic parameters by means of
ray-tracing or other numerical methods might not be economically feasible for a large number of spaces in many development projects. In this paper, we present a deep learning framework and results based on a sequence processing recurrent neural network to predict several room acoustic parameters.
The deep learning models yield prediction speed improvements over ray-tracing or numerical methods, and also significantly improve accuracy over traditional statistical estimation formulas for rectangular rooms. We present the implementation of the method in the soundy.ai application.
Study on noise calculation method considering gear and flap conditions during aircraft landing
Authors: NAKAZAWA Toshiyasu , SHINOHARA Naoaki , SUGAWARA Masayuki , HANAKA Kazuyuki , KOBAYASHI Tomohiro , YAMAMOTO Ryo
Published: December 2023

Looking at recent aircraft noise by component, engine noise has become quieter, while aerodynamic noise such as airframe noise, gear, and flap noise has become relatively louder. Gradually, it has become necessary to take aerodynamic noise into account appropriately. Therefore, using
the regression calculation results of aircraft noise by J-FRAIN, we examined to modify performance data and Noise-Power-Distance (NPD)data, which represent component changes consistent with the AERC model, an existing aircraft noise model in Japan. For performance data, gear and flap parameters
were added to the already used altitude, speed, and thrust. For NPD data, correction NPD data were prepared for the gear and flap changes using the J-FRAIN calculation results. Using these data, noise calculations were performed considering gear and flap status during aircraft landing. In
addition, aircraft landing noise was measured under a flight path of about 30 km around Narita Airport in Japan to confirm the validity of the noise calculation results. Some measured aircraft gear and flap status were obtained and the results of the matched noise calculations were compared
with the measured noise.
Auralization: An Experimental Approach to Understand the Soundscape of the Past
Authors: Djimantoro Michael Isnaeni , Martokusumo Widjaja , Poerbo Heru W. , Sarwono Joko
Published: December 2023

The soundscape attempts to understand the perception of the acoustic environment in a context. However, the soundscape, especially in assessing the perception of the acoustic environment in the context of historic areas, has limitations. While a comprehensive understanding of the present
and past acoustic environment is crucial, audial recordings of the past are not recorded properly. Therefore, this paper aims to explore auralization, as an approach to represent acoustic environments in the past. In this study, participants were stimulated with various historical literature
and photographs to compose the acoustic environment of the past. Although there have been limitations to authenticating acoustic environmental compositions, auralization models can be used as a basis for soundscape research from the past. This approach opens new discussions in historic soundscapes
and the preservation of cultural heritage areas. Keywords: Acoustic Environment, Auralization, Heritage Area, Historic Soundscape, Preservation
Determination of sound-field diffusion indices based on FMBEM incidence directivity analysis
Authors: Hagiwara Ryo , Sakuma Tetsuya , Yasuda Yosuke , Masumoto Takayuki
Published: December 2023

Regarding the diffuseness of sound field, several indices and their measurement methods have been proposed in terms of isotropy of traveling waves. In this paper, we attempt to calculate two kinds of diffusion indices based on the incidence directivity analysis employing the fast multipole
boundary element method (FMBEM). The directivity analysis is performed for steady-state sound fields in a rectangular room with changing the absorption condition of the walls. As for diffusion indices, the directional diffusion coefficient is determined from the deviation of directivity of
sound intensity, while alternative isotropy indicator is calculated through the spherical expansion of the directivity. The numerical results show general tendencies that the former index is almost constant, whereas the latter index decreases with increasing the frequency. As a common tendency,
it is confirmed that the indices become higher in a reflective room condition, and remarkable dips occur around the natural frequencies when absorbing walls are unevenly distributed. Moreover, concerning the receiving cell, the size of it has little effect on the indices. On the other hand,
it is verified that the indices become higher with the receiving cell near the point source.
Evolution of acoustic performance on residential buildings: An analysis from the acoustic tests database since the release of Brazilian acoustic standard performance
Authors: Giner José Carlos , Sá Yann Ardanaz de , Soares Murilo , Rossatto Raquel , Fengler Bárbara
Published: December 2023

In 2013, the Brazilian Association of Technical Standards released the first version of the ABNT NBR 15575 standard, increasing the quality of Brazilian civil construction. The standard presents criteria for acoustic performance levels for residential buildings. A Brazilian acoustic
laboratory from São Paulo city, since the release of the performance standard, has carried out more than 700 acoustic tests in different buildings to evaluate the standard requirements. The purpose of this paper is to investigate the evolution of acoustic performance in the new Brazilian
buildings using this database. It was observed greater interest of the construction companies in the acoustic quality of the buildings from the release of the standard, registering a significant increase in the acoustic tests performed. In 2020, the number of different construction companies
hiring acoustic tests exceeded by 1800% compared to 2013, the date of the performance standard appeared. Additionally, between 2014 and 2022 there was a considerable increase in the acoustic performance of construction systems. Considering only bedroom environments, there was an average increase
of 7 dB in the acoustic performance of internal vertical partitions. As for air noise and floor impact insulation, 7 dB and 10 dB higher performance was observed, respectively.
Causal-based optimization of micro-perforated treatments
Authors: Maury Cedric , Bravo Teresa
Published: December 2023

Enhancing the low-frequency performance of compact acoustical micro-perforated treatments is a challenging task that requires global optimization studies performed on numerical or theoretical models. However, for a given geometry, there always exists a lower frequency bound below which
the treatment will exhibit poor dissipation performance. In this study, it is shown how this lower frequency bound is related to the total integrated dissipated power through a causal-based criterion. Examples are shown for the cases of a rigidly-backed micro-perforate under plane wave incidence
and for a locally-reacting micro-perforated resonant silencer mounted in a duct. Such criterion provides the ultimate bandwidth-to-length ratio that can be achieved by the acoustical treatments for a given target dissipation value. One can also deduce the optimal values of individual parameters
such as the hole diameters or the wall porosity that leads to a suitable balance between leakage and dissipation effects. The causal-based optimized treatments are validated against simulated or measured impedance tube data.
Modeling of Sound Radiation from a Loaded Rolling Tire
Authors: Choi Won Hong , Bolton J. Stuart
Published: December 2023

In recent work it has been possible to model the surface vibration of a loaded rolling tire, including the influence of the acoustic mode that forms within the tire cavity. For example, it has been found that the acoustic cavity mode splits owing to the deformation of the tire when
it is loaded, and that the split widens owing to Doppler effects when the tire is rolling. It has also been demonstrated that the force at the hub that results from the acoustic cavity mode is strongly dependent on interaction with circumferential structural modes of the treadband. The finite
element models developed to-date, thus allow a prediction of the tire's surface vibration. To predict the sound radiation from the deformed, rolling tire, the surface vibration data has been used as the input to boundary element calculations; the effect of the ground surface is modeled by
creating an "image" tire. The calculations have been used to illustrate the nature of the exterior sound radiation that results from the acoustic cavity mode, which can be relatively efficient due to the sonic phase speed of the mode within the tire cavity, as opposed to the subsonic
structural wave propagation along the treadband.