bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic radiation from an engine intake using an admittance multimodal method
Authors: Mangin Bruno , Gabard Gwénaël
Published: December 2023

This paper presents an adaptation of the admittance multimodal method for computing the mean flow around an engine intake and the associated radiated acoustic field. The basic idea is to surround the engine with a fictive duct with a perfectly matched layer on its outer wall which simulates
far-field conditions and avoids any acoustic reflection. The use of matching conditions between this duct and the engine duct allows for calculating the flow and acoustic admittance matrices (and then the associated fields) everywhere. The developed method, initially devoted to acoustic propagation,
can also compute the mean flow field with some adjustments and is very efficient if some assumptions are added (typically an incompressible flow hypothesis in the far-field). The flow and acoustic results are then compared against a finite element method and highlight the accuracy and efficiency
of the proposed approach.
Application of efficient noise control strategy to a vibratory-rotary drilling machine
Authors: Miyazaki Tetsuya , Okabe Shinji
Published: December 2023

We have applied an efficient noise control strategy to a vibratory-rotary drilling machine, which is capable of geothermal hole drilling, water well drilling, etc. In construction works, lowering of noise is a highly required, particularly in urban areas. The drilling machine of this
type is powered by a diesel engine and features a drilling system with a high frequency vibration. A-weighted sound power level of the original model reaches up to 111-116 dB. We have set our reduction target down to about 10 dB. In order to achieve this target noise level efficiently and
quickly, we employed following techniques: (i) Noise sources identification and characterization by an acoustic imaging camera with microphone allay (ii) Prediction of countermeasure effectiveness through ray-acoustics simulation method (iii) Repeated testing and assessment With this strategy,
appropriate measures were designed and were applied to major noise sources. The lower noise target was safely achieved easily and quickly in this case.
Damper arrangement to reduce structure born sound based on structural intensity
Authors: Matsumoto Chihiro , Yamzaki Toru , Kurihara Kai , Kimura Takuto
Published: December 2023

Vibration measures can be taken at three main locations: the vibration source, the propagating part, and the radiating part. However, implementing measures at the vibration source is often challenging, and countermeasures at the radiating part are inefficient. Therefore, measures taken
at the propagation part are typically preferred. To achieve this, the technique of structural intensity (SI) is commonly used, which is effective in understanding the propagation path. In this paper, we propose reducing vibration using a viscous damper layout based on the SI distribution at
the propagation part. We present the most effective layout for vibration reduction in a 3 degree of freedom (DOF) system. Our results show that adding a damper on the response side is effective. Additionally, we discuss the relationship between the ratio of change of SI and velocity for a
flat plate. Based on these findings, we propose a new method for identifying the damper location by SI. The method involves determining the location where the spatial rate of change of SI is highest in the path from the excitation and response points. We verify the effectiveness of our proposed
method on a flat plate and demonstrate its effectiveness on an automobile body for vibration reduction.
Reflected wave manipulation by aeroacoustic metasurfaces in sheared grazing flows
Authors: Qu Renhao , Guo Jingwen , Fang Yi , Yi Wei , Zhang Xin
Published: December 2023

Acoustic metasurfaces (AMs) are artificial structures possessing exotic acoustic properties, such as negative refraction and perfect absorption, etc., in sub-wavelength thickness scales. Most previous studies on AMs were conducted in laboratory conditions with a static medium, limiting
their applications in practical conditions, e.g., the aircraft engines where an aerodynamic background flow is present. To fill this gap, we study the effects of a grazing shear flow on the reflection performance of periodic AMs in this work. An AMs design method is proposed to realize effective
wavefront manipulation with the consideration of the shear flow. The strategy is to form a linear reflected phase-shifting covering 0 to 2π above the shear layer. The reflection characteristics of two acoustic porous metasurfaces (APMs), i.e., APM1 and APM2 designed for the uniform and
the sheared flows, respectively, are numerically investigated. Results show that the presence of the shear layer reduces the effectiveness of APM1 under oblique incident waves due to the considerable refraction effect. In contrast, under the same flow conditions, APM2 realizes desired wave
manipulation behaviors, such as anomalous reflection and surface wave conversion. This study provides guidelines for AMs design in flow conditions, which offers potential for noise control in aeroacoustic problems.
Need for a new test method for determining the acoustic performance of road traffic noise reducing devices
Authors: Oh Yang Ki , Kim Ha Geun
Published: December 2023

Noise reducing devices such as sound barrier walls are common ways to mitigate traffic noise problems in residential areas next to arterial roads or railways. The basic performance of noise reducing devices is sound insulation and absorption. However, the existing measurement methods
are not adequate for characterizing sound insulation and absorption performances of noise reducing devices. The sound insulation measurement method is different from the actual installation condition of the noise reducing devices that transmit the sound to the free field, and the sound absorption
coefficient measurement method does not include the transmitted sound energy. This study raised the problem of the current acoustic performance measurement method of noise-reducing devices and arises the need for a new measurement method to complement it.
Simultaneous perturbation algorithm for active noise control with an asynchronous wireless microphone
Authors: Hou Yiran , Yu Hao , Shi Chuang , Li Huiyong
Published: December 2023

This paper investigates the issues on the use of an asynchronous wireless microphone in an active noise control (ANC) system. In a previous work, the jitter effect of the wireless error microphone is addressed by adopting the simultaneous variable perturbation (SVP) algorithm to update
the control filter of the ANC system. However, another critical issue has been overlooked. The wireless microphone can have a different sampling rate from that of the ANC controller, because the analog-to-digital convertors for the ANC controller and the wireless microphone are triggered by
separate crystal oscillators. This may deteriorate the convergence performance of the ANC system. In this paper, the simulation results demonstrate that both the SVP and online secondary path modeling (OSPM) algorithms are not affected by the sampling rate of the wireless error microphone,
when the sampling rate difference is less than 0.01%. However, the sampling rate difference of the wireless reference microphone can lead to about 7 dB and 5 dB degradations in the noise reduction performance of the SVP and OSPM algorithms, respectively.
A comparison of the classification performance of shallow and deep convolutional neural networks in small active sonar datasets
Authors: Kim Geunhwan , Hwang Youngsang , Shin Sungjin , Shin Myoungin , Choi Jongkwon , Lee Keunhwa , Kim Juho , Choo Youngmin
Published: December 2023

An active sonar system transmits and receives a pulse with a short duration to detect and track underwater targets. The detection shrinks candidates for the targets with multiple contacts; some of them are the actual targets. Classification is conducted to find the targets among the
contacts. Previous classification studies have used conventional machine learning techniques including support vector machines and displayed limited performance. Due to the recent remarkable development of deep learning using deep neural networks, it is being introduced to active sonar classification.
However, superior performance of deep learning is guaranteed when big data are available. In the active sonar classification, deep learning-based classification performance may deteriorate due to the small active sonar dataset, and shallow networks could be alternative. Here, we compare and
analyze the classification performance of shallow and deep convolutional neural networks using in-situ active sonar datasets.
Experimental study on reading disturbance by combining two-axis vibration and noise
Authors: MORIHARA Takashi , Matsumoto Yasunao , Yokoshima Shigenori , Hayashi Kentaro
Published: December 2023

We conducted an experimental study for the combined effect of noise and vibration. This study shows two results of the experiments. The first is the result of an experiment on activity disturbance by a combination of horizontal and vertical vibration stimuli from automobiles and trains,
and the second is the result of an experiment combining dual-axis vibrations and noise stimuli. The vibration stimuli were four levels and noise stimuli were two levels. Noise-vibration combination experiment was used sound stimuli with peak levels of 50dB and 60dB. Thirty or twenty students
participated in these experiments. Both railway stimuli and automobile stimuli in the high vibration condition, reading disturbance on the combined stimuli of horizontal (lateral direction) and vertical vibration stimuli were higher than that on the only one axis vibration stimulus. As a result
of ANOVA, the reading disturbances in the including noise condition were higher than that in the condition of vibration stimuli only. In addition, the reading disturbances were high in the large vibration stimuli conditions.
FE-based Simulation of Radiated Noise for a Rotating Tire
Authors: Kim Ilsik , Kim HyunUk , Kim YongHun
Published: December 2023

Today, the significance of reducing pass-by noise is increasing steadily due to EU labeling regulations and the demands of car makers. As a result, numerous companies are actively conducting research to minimize pass-by noise. In this paper, we introduce a finite element method (FEM)
prediction technique for reducing pass-by noise, aimed at reducing the time and cost involved in manufacturing, testing, and verifying pass-by noise. We have created a tire FE model that incorporates the full pitch sequence of the tire pattern, and used it to predict airborne noise (ABN) generated
by air pumping and vibration due to the grooves in the pattern. The simulation environment was designed to match the test conditions in Hankook's anechoic chamber, and we compared the frequency spectrum of the simulation results with the actual test results. In conclusion, we have successfully
performed FEM simulation of radiated noise, which accurately reflects the noise generation mechanism of rotating tires. This has improved the simulation accuracy for predicting airborne noise.
Dynamic Young's modulus measurement by incident wave extracting for viscoelastic materials under variable water pressure
Authors: WANG Bing , LIU Zhe , ZHANG Zixuan , HOU Hong
Published: December 2023

This study presents a method for measuring the complex Young's modulus of viscoelastic materials under several water pressures. A Butterworth impulse is generated by an electromagnetic shaker and is employed to excite a bar-like sample which was attached inside the pressure vessel.
The broadband mechanical parameters (including the storage modulus and loss factor) under variable water pressure conditions (0.1-5MPa) for two types of viscoelastic materials were obtained by incident wave extracting. The experimental results agree well with those obtained using a standard
dynamic mechanical thermal analyzer and those obtained using resonant method, which proved that the method proposed in this study can directly determine the Young's modulus at frequencies ranging from 500 to 5000Hz under variable water pressure. This method provides simplified processing for
underwater dynamic mechanical parameters measurements.
Investigation for recent trend of the extraordinary tonal sounds observed from landing aircraft and its influence on noise evaluation
Authors: Hanaka Kazuyuki , Shinohara Naoaki , Nakazawa Toshiyasu , Shimoyama Koji
Published: December 2023

We have been investigating the extraordinary tonal sound emitted from landing aircraft for some time. The extraordinary tonal sound has the characteristics of pure tones with a prominent specific frequency and has a short duration and a prominent level fluctuation. The results of a
study conducted at Narita Airport about 15 years ago showed that the incidence was high for the B777, the most advanced aircraft type at the time. It was also found to have a little effect on WECPNL, the aircraft noise rating at the time, and the degree of influence was small. Some of these
extraordinary tonal sounds existed differently than they did 15 years ago, which could be confirmed by the latest GTF-engine-equipped aircraft. Furthermore, in Japan, the aircraft noise evaluation index has changed from WECPNL to Lden compared to 15 years ago. In this study, based on the results
of surveys conducted at several airports in Japan, we report on the current situation in which the aircraft type composition has changed, and we again examined the actual occurrence of this extraordinary tonal sound and its impact on the evaluated amount of aircraft noise.
A preliminary study on the effect of rough sound on discomfort
Authors: Lv Bingcong , Huang Yu , Miao Zhenjing
Published: December 2023

Acoustic roughness was proposed as a psychoacoustic metric, indicating that rough sound would attract attention or cause unpleasant feelings. Noting that some previous studies have found a negative relation between roughness and discomfort caused by noise, we intend to investigate the
effect of roughness on discomfort. The 1000Hz tone was amplitude modulated with the modulation frequency range of 10-140Hz and a modulation depth of 100% as the test stimuli. Forty-eight subjects rated the discomfort caused by the test stimuli relative to the reference stimulus having a standard
1 asper roughness (i.e., 1000Hz tone with a modulation frequency of 70 Hz and a modulation depth of 100%) using the method of relative magnitude estimation. Each stimulus had a sound pressure level of 60 dB and a duration of 1 second. We identified a nonlinear pattern of discomfort with the
increasing modulation frequency, with the lowest discomfort for the standard 1 asper roughness at a modulation frequency of 70 Hz. A modification weighting dependent on the modulation frequency would better quantify the roughness metric to reflect the effect of rough sound on discomfort.
Sound Event Detection utilizing Spectro-Temporal Receptive Field
Authors: Min Deokki , Nam Hyeonuk , Park Yong-Hwa
Published: December 2023

Sound event detection (SED) is a task of recognizing the target sound events with their respective onset and offset time in a recorded audio clip. SED is closely related to auditory scene analysis, the process by which human auditory systems perceive sound into perceptually meaningful
components. While human auditory system is trained to perform SED well enough, the way sound is transformed into neural response within human auditory system still remain as the subject of ongoing research. One of efforts to describe the relationship between sound and neural response is the
spectro-temporal receptive field (STRF). STRF acts as a linear function between sound time-frequency representation and primary auditory cortex (A1) cell response, so that neural response can be predicted by convolution of time-frequency representation of sound and STRF. In addition, STRF
is designed to capture spectro-temporal modulation in that A1 cells are much reactive to spectro-temporally modulated ripple. In this work, we utilized STRF as a kernel of the first layer in the convolutional neural network (CNN) to extract neural response from input audio clip to make SED
model similar to human auditory system. Then, we constructed two-branched SED model named as Two Branch STRF-Net (TB-STRFNet) composed of STRF branch and basic branch. The STRF branch extracts spectro-temporal modulation information and the basic branch extracts detailed and complex time-frequency
information. TB-STRFNet outperformed the baseline by 4.3% in terms of main metric in DCASE 2023 Task 4 subtask B.
Evaluation of Psychoacoustic Parameters on Internal Combustion Engine Vehicle and Electric Vehicle: Case Study of Armored Vehicle
Authors: Nabila Ajeng Nazla , Sarwono R. Sugeng Joko , Sudarsono Anugrah Sabdono , Nitidara Ni Putu Amanda , Zakri Keysha Wellviestu
Published: December 2023

In this study, psychoacoustic evaluation was performed to identify the sound characteristics of the armored Internal Combustion Engine Vehicle (ICEV) and Electric Vehicle (EV) based on the loudness, roughness, and sharpness parameters. The evaluation was performed on both static and
dynamic conditions such as engine on, engine on with AC, constant speed of 20 km/h on smooth roads, and acceleration. The results showed that under the engine on and acceleration conditions, significant differences were found in loudness (0.7-18.4 sone average difference), roughness (0.035-0.058
asper average difference), and sharpness (0.16-0.28 acum difference on average). Meanwhile, there was no significant difference in the Roughness parameter between ICEV and EV on the condition of the engine on with AC and a constant speed of 20km/hour on a smooth road. Significant differences
were found in loudness (1.6-4.2 sones average difference) and sharpness (0.11-0.27 acum average difference). Based on the test results in this study, it can be seen that there are differences in sound characteristics between ICEV and EV so that they can cause different perceptions from users.
Quasi-real-time estimation of a loudspeaker direction from sound pressure level ratio among four channels
Authors: Tsuda Ryusei , Awatani Tomoru , Nakayama Masato , Takahashi Toru
Published: December 2023

This paper describes a quasi-real-time estimation method of loudspeaker direction under Gaussian noise environment. Our estimation method is based on sound pressure level ratio among four channels when the loudspeaker is surrounded by four microphones. Performance of our method tends
to be better when acoustic spatial radiation characteristics of sound source is skewed. Preliminary experiments show that an offline processing version of our method is more than 99% accurate in acoustically clean environments. In this paper, we discuss the noise robustness of our method through
simulation experiments. Loudspeaker direction is estimated from 0.34s segments of Japanese sentences every 0.01s, that is quasi-real-time processing. Those segments are contaminated by Gaussian noise at 0dB, 10dB, 20dB. We demonstrate that the proposed method is robust to Gaussian noise. The
results show that accuracies of proposed method (Prop2) are 96.9%, 98.2%, 98.4% at the band the center frequency of which is 2000Hz.
Auditory masking based on automatic chord progressions using modulation conditions of critical bandwidth in diatonic chords for dental treatment sounds
Authors: HAYASHI Takuya , TAKAHASHI Toru , NISHIURA Takanobu , NAKAYAMA Masato
Published: December 2023

The unpleasant noise is one of the important social problems because our quality of life is degraded by it. We have previously proposed the comfortable sound design method based on chord-forming with music theory for dental treatment sounds. The previously proposed method is difficult
to apply various dental treatment sounds because that employs single chord progression. To solve this problem, we focus on the automatic generation of chord progression by using diatonic chords. In this paper, we propose an auditory masking method based on the automatic generation of chord
progression using diatonic chords with the key determined from the peak frequencies of dental treatment sounds. The proposed method employs the modulation conditions of critical bandwidth in diatonic chords for comfort in the modulations. The proposed method can achieve suitable sound design
for various dental treatment sounds by utilizing real-time key determination according to the peak frequency of dental treatment sounds. Finally, we confirmed the effectiveness of the proposed method through evaluation experiments.
Using infrared radars for ear positioning in active noise control headrests
Authors: Li Hang , Chen Kai , Tao Jiancheng , Qiu Xiaojun
Published: December 2023

Active noise control headrests reduce low frequency noise around human ears based on active noise control technology, in which accurate positioning of human ears is required to achieve good noise reduction performance when the human head moves. In this paper, infrared radars are used
in an active noise control headrest by installing them around the human head. Three infrared radars are used, which face the left, the right and the back sides of the human head separately in a horizontal plane. The location of each ear is estimated by searching the abnormal bulges from the
scanned contour line of the human head. The positioning ability of the proposed system for both translating and rotating movements of human head and the improvement of noise reduction are investigated based on the experiment measurements. The effective range, positioning accuracy and the limitations
of the proposed method are further discussed.
The influence of structural changes and defects on noise mitigation properties of the periodic structures based on coupled Helmholtz resonators
Authors: Pavliuk Aleksandra , Krasikova Mariia , Krasikov Sergey , Melnikov Anton , Baloshin Yuri , Powell David A. , Marburg Steffen , Bogdanov Andrey
Published: December 2023

The work is dedicated to investigation of several ways for optimization of periodic structures based on coupled Helmholtz resonators. Such modifications as chirped lattices, arbitrary defects, and supercells, are explored. We analyze widening of stop-bands associated with the introduction
of these structural changes and how they affect the corresponding noise mitigation properties. Utilizing numerical calculations we find optimal parameters of the considered structures and study the dependence of transmission coefficient on various geometric parameters of the system. As a main
result, we demonstrate the merging of several stop-bands leading to ultra-broadband noise mitigation. The achieved enhancement is linked to the properties of the equivalent infinite structures and their eigenmodes.
The Covid-19, an unexpected "tool" to assess the chances of reaching the WHO recommended noise limits in medium-sized cities
Authors: Vílchez-Gómez Rosendo , Montes-González David , Rey-Gozalo Guillermo , Morillas Juan Miguel Barrigón , Sánchez-Fernández Manuel
Published: December 2023

Noise is one of the main health problems in cities. The World Health Organization (WHO) has recommended a limit for both the day-evening-night noise indicator (Lden) and the night-time noise indicator (Ln). Values above these limits are associated with adverse health effects. Given
that the main source of noise is road traffic, the question that arises is whether these limits can be achieved in a reasonable period without substantially altering the economic or social activities that usually take place in the city. The SARS-CoV-2 pandemic has prompted governments in many
countries to take extreme measures to reduce the spread of the virus. Typically, the most widespread measure has been to reduce citizens' mobility and gatherings. It is in this context of extreme disruption of the daily activity of a city where we can analyse whether the limits for the noise
indices proposed by the WHO have been reached and, therefore, we have achieved quiet and healthy cities in compliance with these limits. In this work, we analyse the sound situation in an urban environment before and after the appearance of SARS-CoV-2 and we analyse whether the objectives
of the WHO have been reached.
Sound Insulation Study of Modular Integrated Construction
Authors: Ng H.T. , Chan C.K. , Ng C.W. , Baeck I.W.
Published: December 2023

Recently, Modular Integrated Construction (MiC) has been considered as one new trend of construction method for some applications in Hong Kong due to its ease/speed of installations, build efficiency and environmental benefits. The acoustic performances of typical MiC units in Hong
Kong have been investigated. The acoustic findings are analyzed and adopted to compare standards in some other cities over the world and other common constriction in order to derive possible new types of constructions in Hong Kong to improve the building neighboring noise complaints by residents.
Identifying contextual factors of soundscape based on mental mapping and caption evaluation methods
Authors: Kim Geon-Hee , Kim Tae-Hui , Hong Joo-Young
Published: December 2023

Context is one of the important factors in analyzing and understanding soundscapes. Various methods for evaluating soundscapes such as soundwalks, questionnaire surveys, and narrative interviews have been proposed in ISO 12913-2. However, these methods are still limited to providing
a holistic approach to identifying contexts in a place. This study aims to propose a systematic approach combining mental mapping and caption evaluation methods to identify various contexts for soundscape evaluations. The experiment consisted of two sessions. In the first session, contexts
related to places were evaluated using mental mapping. Participants were asked to draw perceived landscape factors (i.e., paths, edges, and landmarks) and soundscape factors (i.e., negative or positive sounds) on the maps. Throughout this session, geospatial data of landscape and soundscape
were visualized using frequency analysis and kernel density estimation. In the second session, contexts associated with people and activities are assessed using the caption evaluation method. Participants were asked to describe soundscape elements with their characteristics, impressions, and
judgment. Then, the collected text data on soundscapes were analyzed through text mining techniques.
The characteristics of the acoustic environment and the restorative benefits of soundscape in interventional therapy rooms
Authors: Tian Yu , Xie Hui , Xiao Kai Hu , Lv Wang Yang , Liu Chang
Published: December 2023

Coronary heart disease (CHD) has become one of the most serious health problems in the world. As a treatment environment for CHD, the acoustic environment in the interventional therapy room is crucial to patients and healthcare workers. To investigate the characteristics of the sound
environment in interventional therapy rooms and the soundscape health benefits of the soundscape for patients, acoustic measurements and noise behavior observations were conducted in various areas of an interventional therapy room, and soundscape intervention experiments were performed on
patients treated there. In this study, CHD patients were used as the research object. Results show that: 1) the background noise levels for waiting area (WA) and operation area (OA) under empty field conditions were 54.5 dBA and 52.8 dBA, and 66.43 dBA and 64.2 dBA, respectively, under conditions
of usual use. 2) Patients perceived the acoustic environment as noisy and uncomfortable in both areas, with OA being more severe than WA. 3) Natural sounds from composite sources has a greater potential for restorative benefits than single-source soundscape.
Impedance measurements on reflective surfaces: effect of nodes
Authors: Blokland Gijsjan van , Sohaney Richard C. , Schwanen Wout
Published: December 2023

The ISO 13472-2 standardizes the in-situ measurement of normal-incidence acoustic absorption of road pavements. The standard describes the use of the two-microphone method with an impedance tube specially configured for sealing against pavement surfaces. The method is of interest to
the tire-pavement noise and vehicle pass-by noise communities. For roads constructed of dense graded asphalt, for example, pass-by noise test tracks conforming to ISO 10844, the pavement is a highly reflective surface. Under this measurement condition, the acoustic field within the tube develops
nodes at one or the other microphone positions at characteristic frequencies. These nodes present as sharp peaks and valleys in the two-microphone transfer function. Such narrow bandwidth features are susceptible to measurement error, in particular, signal processing leakage as evidenced by
significant drops in the coherence function at the frequencies of the nodes. In this paper we study the nature of the nodes and the effect they have on the two-microphone transfer function and coherence function. We further investigate how different formulations of the transfer function affect
the overall 1/3rd octave band accuracy. The effect of the number of averages on both coherence and leakage error is assessed. The potential to solve this leakage effect by switching microphones to other positions is evaluated in relation to a procedure with two fixed microphones. It was concluded
that although shifting microphone positions does have advantages in terms of preventing leakage, the mandatory application of a reference measurement reduces the overall error. Finally, recommendations for improving the procedure in ISO 13472-2 are formulated.
A Computation-efficient Online Secondary Path Modeling Technique for Modified FXLMS Algorithm
Authors: Ji Junwei , Shi Dongyuan , Gan Woon-Seng , Shen Xiaoyi , Luo Zhengding
Published: December 2023

This paper proposes an online secondary path modelling (SPM) technique to improve the performance of the modified filtered reference Least Mean Square (FXLMS) algorithm. It can effectively respond to a time-varying secondary path, which refers to the path from a secondary source to
an error sensor. Unlike traditional methods, the proposed approach switches modes between adaptive ANC and online SPM, eliminating the use of destabilizing components such as auxiliary white noise or additional filters, which can negatively impact the complexity, stability, and noise reduction
performance of the ANC system. The system operates in adaptive ANC mode until divergence is detected due to secondary path changes. At this moment, it switches to SPM mode until the path is remodeled and then returns to ANC mode. Furthermore, numerical simulations in the paper demonstrate
that the proposed online technique effectively copes with the secondary path variations.
Prediction of the wall pressure spectrum over a curved structure excited by a non-homogeneous turbulent boundary layer in water
Authors: Trafny Nicolas , Serre Gilles
Published: December 2023

In the present study, we introduce a volume approach based on the Poisson equation solved using a Green's function and a semi-analytical turbulence model in space domain. This model can be built from either a Reynolds-Averaged Navier-Stokes (RANS) simulation or an estimation of the
boundary layer parameters. Predictions for the power spectral density of the wall pressure fluctuations are compared against measured data obtained for various flow conditions inside a cavitation tunnel. Two geometries are considered. First, we use a NACA 0012 hydrofoil of constant chord length
to validate predictions for different flow velocities and angles of attack. Then, we consider a NACA 0009 hydrofoil with a spanwise varying chord length to investigate the contribution of three-dimensional effects.
Sound Power Measurement of Tyre/Road Noise Using the Close-Proximity (CPX) Trailer Enclosure
Authors: LI Dong Fang , LEUNG Randolph C. K. , RAI Sanjaya
Published: December 2023

The present paper reports a new methodology for measuring the sound power level (SWL) of tyre/road noise, using a modified Close-Proximity (CPX) trailer enclosure. Specially designed diffuser panels are implemented to cover the absorption materials on the interior walls and ceiling
of the CPX enclosure to create a reverberant chamber. Through numerical simulations, the optimal reverberant chamber design, which holds the least acoustic resonance and most uniform acoustic energy distribution, is determined to guide fabrication. The SWL of a reference sound source (RSS)
is determined first. The sound pressure level (SPL) distributions inside the reverberant chamber with the RSS switched on are then obtained under static conditions and road tests. The relationships between the SWL of the RSS and the SPL it produces inside reverberant chamber with various RSS
inputs signals show great consistency with theory. Using the linear regression of SWL with respect to spatially averaged SPL reverberant chamber obtained in static condition, the total SWL and its spectrum at a specific vehicle speed can be deduced from the captured SPL information inside
the chamber during road tests with the RSS switched off.
Fundamental study on directivity of acoustic radiation from tire by using ray tracing method
Authors: Kurihara Kai , Shirahashi Yoshihiro , Okamoto Ryota , Yamazaki Toru
Published: December 2023

Ray tracing method is classified as a geometric acoustic theory and is a commonly used method for analysing sound field in buildings. It traces the reflection and propagation paths of a number of sound rays radiated from a sound source. Originally, ray tracing method does not take frequency
response into account, but in this study, ray tracing method is modified so that frequency response can be calculated in order to apply ray tracing method to general sound field analysis other than buildings. For this purpose, the propagation distance of each sound ray due to reflection are
considered, and the interference of each sound ray at the receiver is calculated. To verify the effectiveness of the proposed method, it is applied to the acoustic radiation of tire noise as an example. In addition, the directivity of the tire noise acoustic radiation is investigated on the
basis of ray tracing method.
Reduction of Flow-Induced Trailing Edge Noise of Semi-Infinite Flat Plate by Structural Resonance
Authors: ARIF Irsalan , LEUNG Randolph C. K. , NASEER Muhammad Rehan , SALAMAT Shuaib
Published: December 2023

A unique method for the reduction in flow-induced trailing edge noise scattering for a semi-infinite thin plate is proposed by utilizing short flexible panels mounted on the surface of the plate. The proposed configuration differs from conventional cantilevered elastic trailing edges
due to the limitations of their structural integrity and applicability. The key idea is to design short panels that vibrate in structural resonance under the fluid loading for absorbing the energy from the flow to sustain their vibration. A time-domain direct aeroacoustic simulation coupled
with structural dynamics is carried out at a low Reynolds number of 50,000 to explore the aeroacoustic-structural interactions. The effectiveness of noise reduction of the designed configuration is analyzed by comprehensive aeroacoustic analysis where a significant noise reduction is observed
for the plate mounted with three flexible panels without any adverse effects on the plate aerodynamics. The structural analysis shows a systematic vibration pattern for all the panels which clearly indicates the presence of complex fluid-structural interaction under resonance conditions. Design
strategy of the proposed configuration along with its limitations are also discussed.
Vibration analysis of drum membrane using computer vision
Authors: Singh Lokendra , Gupta Arpan
Published: December 2023

The real time experience of what one sees and what one hears is enriching but if one can visualize what is audible will be fascinating. We suggest a simpler approach for sound localization that directly collects motion signals based on visual movements. In this study, frequency has
been detected at various location of drum using computer vision method. A smartphone camera set up on a tripod next to the drum has captured these vibrations at approximately 240 frames per second. To determine the frequency, a Fourier analysis was performed on the data collected from the
frames. We detected frequency of ~94 Hz at multiple spots by analyzing the motions of a point or region of interest (ROI) at membrane of drum. The frequency of drum membrane detected by a mobile microphone was found to be equivalent to the frequency observed using the proposed computer-vision
method. Similar concepts can be employed in understanding the fundamentals of sounds generated by various musical instruments.
Acoustic contrast control in two regions in car cabins
Authors: Wang Shuping , Zhu Qiaoxi , Tao Jiancheng , Qiu Xiaojun
Published: December 2023

Personal audio systems that generate different sound zones in different regions have received much interest recently, especially in car cabins. The feasibility of creating a listening zone at the driver's seat and a quiet zone at the passenger's seat with the headrest speakers, door
loudspeakers, and the combination of them is investigated in this manuscript. A finite element model of a car interior is created in COMSOL Multiphysics to obtain the acoustic transfer functions and the acoustic contrast control performances of 4 different speaker configurations are compared
with each other. It is found that the 4 headrest speakers achieve better acoustic contrast control performance than the door speakers at low frequencies, while the sound pressure level distribution tends to be more uniform in the bright zone when using the door speakers.
Airless tires in the LEON-T project: How can they reduce tire/road noise emission
Authors: Sandberg Ulf
Published: December 2023

For more than a century, pneumatic tires (inflated with air) have totally dominated the market for road vehicle tires. However, in the recent two decades, interest has grown in developing airless tires; tires whose load is not carried by the inflation by air, but by the mechanical structure
that connects the belt and rubber tread with the hub. The EU project LEON-T includes a part in which prototypes for innovative heavy goods vehicle (HGV) tires are developed, with the main purpose to reduce noise emission by 6 dB. To reduce noise that much it is believed that airless tires
are needed. In LEON-T, two airless tire prototypes are intended to be developed by partner Euroturbine, in cooperation with other partners and subcontractors. Originally, the load-carrying material was intended to by composite material (reinforced plastic), but initial calculations have shown
that a stronger material is needed; consequently, steel springs are currently being used. This paper will describe the principle of airless tires but with focus on the version being developed in LEON-T. The main part of the paper will deal with the noise generation mechanisms and the ways
that airless tires can reduce the noise emission are thoroughly identified and discussed.
Variation of the secondary acoustic paths from loudspeakers at the seat shoulder in an automobile cabin
Authors: Yang Ziyi , Wang Youfan , Tao Jiancheng
Published: December 2023

The secondary path is essential in the design of adaptive active noise control systems, and it varies with several factors in practical implementation. In this paper, the acoustic responses from secondary loudspeakers installed at the shoulder of the front passenger seat to the error
microphones at the passenger's ears in an automobile cabin are measured, when the factors including the passenger movement, the seat posture and the passenger number change. The upper limit frequency where the phase variation is within 90 deg. compared to the reference position is analyzed.
The results show that the state of both the passenger head and the seat back determines the lowest upper limit frequency among all the factors under investigation. If multiple factors change at the same time, the upper limit frequency will be further reduced.
Comparison of different methods to determine the sound reduction index R of walls
Authors: Verbandt Filip , Vandendriessche Jan , Velde Bart Van de
Published: December 2023

The laboratory method (ISO 10140-2:2021) is probably the most accurate method to determine the sound reduction index R of walls. Flanking noise (ISO 10848-1 and 4:2017) is almost fully eliminated in the laboratory setup whereas this is not the case for in situ measurements (ISO 10052:2021).
The measurements are even more difficult for measurements in open air or in factory halls with mock-up setups. Manufactures of building elements, such as prefabricated walls, are interested in quick measurements of the sound reduction index R of their products. This paper compares the traditional
laboratory measurements, the intensity method and the Sopranoise road barrier method (EN 1793-6) with the vibration velocity / sound pressure method (ISO 140-4:1998). Different setups were measured using different methods in laboratory and in open air. Most of the experiments were done with
loudspeakers used as an excitation source, but some were also done with shakers and a tapping machine. The importance of the use of sound shielded accelerometers will be elucidated.
Vibration of microperforated plate with spatial distribution of multiple-sized perforations
Authors: Gallerand Lucie , Legrand Mathias , Dupont Thomas , Leclaire Philippe
Published: December 2023

Recent works by the authors on homogeneous MPPs have highlighted the structural damping capabilities of MPPs in the low frequency range. The developed theoretical approach was based on the analogy between an MPP and a porous plate. The added damping is due to visco-thermic effects coupled
to fluid-structure interactions. The added damping maxes out at a characteristic frequency depending on perforation diameter. In order to reduce plate vibrations, it was advised to match the characteristic frequency to a plate mode. It is proposed here to maximize the added damping effect
on several vibration modes by focusing on MPPs with multiple-sized perforations and with spatial distribution of perforations. As an extension of the previous analytical model, an approach based on the electro-acoustic analogy is established to capture the effect of multiple-sized perforations.
Moreover, a perforation ratio gradient is included in the approach to model an MPP with inhomogeneous spatial distribution of perforations. Experimental measurements on MPPs validate the proposed analytical model. Results show that: (i) MPP with multiple-sized perforations increases the frequency
band of the effective damping; (ii) the added damping increases when the perforations are distributed around the antinodes of the considered mode, (iii) the two effects can be combined.
Impact of Traffic Noise and Apartment Building Features on the Quality of Life in Matsue City
Authors: Nguyen Tran Thi Hong Nhung , Matsuoka Sosuke , Nguyen Thu Lan
Published: December 2023

Traffic noise has a significant impact on the health and quality of life of urban residents. Despite this, there has been limited research on the effects of vehicle-generated noise from roads and parking lots near buildings. This study aimed to examine the impact of traffic and parking
noise on residents living in apartments along 11 roads in Matsue City, Japan. To achieve this, the residents' reactions to noise were investigated in relation to the distance of their apartments from main roads and parking lots, as well as the building design. Noise exposures were measured
on the road shoulders in front of the properties for 24 hours, and short-term recordings were taken at various reference locations within the buildings. A questionnaire was distributed to 60 households residing in the targeted properties. The results showed that the residents living in apartments
along the main roads, which exceeded the noise level limit recommended by the latest World Health Organization (WHO) environmental noise guidelines, expressed annoyance with the traffic noise. The study highlights that the noise issue cannot be solely determined by comparing it to the environmental
standards recommended by prefectural standards. The findings suggest the need to review whether the current environmental standards are appropriate for each region.
An analysis of a feedback active noise control system using the remote microphone technique
Authors: Shi Li , Zou Haishan , Qiu Xiaojun , Chen Kai
Published: December 2023

This paper examines strategies in virtual sensing feedback active noise control systems and compares the noise reduction performance of three strategies: using physical microphones for direct feedback control, using virtual microphones for direct feedback control, and using physical
microphones for indirect virtual feedback control. For a primary sound field with incident waves in a single direction, simulation results indicate that employing a physical microphone for indirect virtual feedback control consistently yields superior noise reduction performance than that
using a physical microphone for direct feedback control. However, if the causal requirement between physical and virtual microphones is not satisfied, the increase in the equivalent secondary path delay deteriorates noise reduction performance while utilizing physical microphones for indirect
virtual feedback control. For a primary sound field containing waves from multiple directions, the simulation results show that the noise reduction performance is affected by both the coherence and causality between the physical and virtual microphone signals.
A 2.5D hybrid SBM-MFS methodology for the evaluation of free-field vibrations induced by underground railway infrastructures
Authors: Liravi Hassan , Arcos Robert , Clot Arnau , Godinho Luís , Conto Kenny F.
Published: December 2023

In this paper, a new meshless methodology to predict underground railway-induced vibrations is presented. In contrast to previous approaches, the proposed method uses meshless methods to model both the railway tunnel structure and the wave propagation in the surrounding soil. The method
has been evaluated in the framework of an example of railway-induced vibrations using a shell with a square cross-section, embedded in a homogeneous full-space. The method is verified against an analytical solution considering different types of boundary conditions and compared with the 2.5D
FEM-SBM and the 2.5D FEM-BEM approaches in terms of accuracy and computational efficiency. The presented comparisons illustrate that the proposed approach is a suitable strategy for predicting underground railway-induced vibrations, both in terms of accuracy and computational efficiency. Moreover,
the use of meshless approaches for modelling both tunnel and soil not only simplifies the implementation of the approach but also makes it easier to use. Consequently, the proposed approach is found to be a suitable alternative tool for the prediction of railway-induced vibrations.