Pub Date : 2024-11-21DOI: 10.1016/j.apacoust.2024.110423
Anita Drewnicka , Anna Michalak , Radosław Zimroz , Anil Kumar , Agnieszka Wyłomańska , Jacek Wodecki
This paper presents a novel method for fault detection in vibration/acoustic signals contaminated with non-Gaussian noise, specifically addressing the challenge of random impulsive and wideband disturbances in industrial measurements. While damage detection in Gaussian noise environments is well understood, high-amplitude non-cyclic impulsive disturbances arising from random aspects of industrial processes, such as non-uniform operations and random impacts, pose significant analytical challenges.
The proposed method analyzes the distribution densities of spectral vectors derived from spectrograms. It considers a simple additive model consisting of the signal of interest (SOI) and Gaussian and non-Gaussian noise. Using the density-based spatial clustering algorithm (DBSCAN), the method isolates distinct classes of spectral vectors from the spectrogram, effectively separating different signal behaviors and extracting fault-related information. The effectiveness of the proposed method was validated using an envelope spectrum-based indicator (ENVSI) and successfully demonstrated on real signals from an industrial machine with a faulty bearing.
{"title":"A method for signal components identification in acoustic signal with non-Gaussian background noise using clustering of data in time-frequency domain","authors":"Anita Drewnicka , Anna Michalak , Radosław Zimroz , Anil Kumar , Agnieszka Wyłomańska , Jacek Wodecki","doi":"10.1016/j.apacoust.2024.110423","DOIUrl":"10.1016/j.apacoust.2024.110423","url":null,"abstract":"<div><div>This paper presents a novel method for fault detection in vibration/acoustic signals contaminated with non-Gaussian noise, specifically addressing the challenge of random impulsive and wideband disturbances in industrial measurements. While damage detection in Gaussian noise environments is well understood, high-amplitude non-cyclic impulsive disturbances arising from random aspects of industrial processes, such as non-uniform operations and random impacts, pose significant analytical challenges.</div><div>The proposed method analyzes the distribution densities of spectral vectors derived from spectrograms. It considers a simple additive model consisting of the signal of interest (SOI) and Gaussian and non-Gaussian noise. Using the density-based spatial clustering algorithm (DBSCAN), the method isolates distinct classes of spectral vectors from the spectrogram, effectively separating different signal behaviors and extracting fault-related information. The effectiveness of the proposed method was validated using an envelope spectrum-based indicator (ENVSI) and successfully demonstrated on real signals from an industrial machine with a faulty bearing.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"230 ","pages":"Article 110423"},"PeriodicalIF":3.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1016/j.apacoust.2024.110422
Xiyue Ma , Tao Liu , Lei Wang , Kean Chen
This paper investigates the sound absorption performance of hybrid active and passive micro-perforated panel absorber (MPPA) for suppressing the enclosed sound field. The hybrid MPPA is strongly coupled with the enclosed sound field so that it serves as a sound energy dissipating component, rather than a uniform absorption boundary. The in situ sound absorption is highly dependent on its layout on the boundary of the enclosed space, which is worth exploring in depth for aiding in its practical application. The fully coupled enclosure-hybrid MPPA model is established using modal analysis approach. The evolution mechanism of passive and active sound absorption performance in various layout situations are explored both for rectangular and irregular enclosed space, thus providing guidance for layout optimization. Simulations show that the energy dissipation of partial MPPA coverage with appropriate layout is better than the full coverage case. The dissipation when partial covered MPPA locating at the corner is more significant than that at the middle position for rectangular enclosed space. The weakened coupling effects between the enclosure and the MPPA cavity mainly result in the significant dissipation on resonances of the coupled system. Since the irregular cavity modes significantly weaken the above coupling effects, the dissipation of full coverage case is the best for irregular enclosure. Applying active control to suppress the sound field of the MPPA cavity can generate pressure difference across the MPP, which dissipates energy of the undamped resonances of the coupled system to a minimum until a new equilibrium state is reached. The pressure release strategy is applicable both for full and partial coverage cases. The partial covered MPPA needs to be located in the corner to guarantee the control performance of such strategy, meaning that active control requires the cooperation of passive control to achieve better performance.
{"title":"Layout optimization and mechanism analysis of hybrid active and passive micro-perforated panel absorber for suppressing enclosed sound field","authors":"Xiyue Ma , Tao Liu , Lei Wang , Kean Chen","doi":"10.1016/j.apacoust.2024.110422","DOIUrl":"10.1016/j.apacoust.2024.110422","url":null,"abstract":"<div><div>This paper investigates the sound absorption performance of hybrid active and passive micro-perforated panel absorber (MPPA) for suppressing the enclosed sound field. The hybrid MPPA is strongly coupled with the enclosed sound field so that it serves as a sound energy dissipating component, rather than a uniform absorption boundary. The in situ sound absorption is highly dependent on its layout on the boundary of the enclosed space, which is worth exploring in depth for aiding in its practical application. The fully coupled enclosure-hybrid MPPA model is established using modal analysis approach. The evolution mechanism of passive and active sound absorption performance in various layout situations are explored both for rectangular and irregular enclosed space, thus providing guidance for layout optimization. Simulations show that the energy dissipation of partial MPPA coverage with appropriate layout is better than the full coverage case. The dissipation when partial covered MPPA locating at the corner is more significant than that at the middle position for rectangular enclosed space. The weakened coupling effects between the enclosure and the MPPA cavity mainly result in the significant dissipation on resonances of the coupled system. Since the irregular cavity modes significantly weaken the above coupling effects, the dissipation of full coverage case is the best for irregular enclosure. Applying active control to suppress the sound field of the MPPA cavity can generate pressure difference across the MPP, which dissipates energy of the undamped resonances of the coupled system to a minimum until a new equilibrium state is reached. The pressure release strategy is applicable both for full and partial coverage cases. The partial covered MPPA needs to be located in the corner to guarantee the control performance of such strategy, meaning that active control requires the cooperation of passive control to achieve better performance.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110422"},"PeriodicalIF":3.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1016/j.apacoust.2024.110416
Long Xu , Minglong Wang , Hui Li , Xiaozhen Li , Teng Wu , Chunguang Wang , Zhandong Huang , Peipei Jia , Jun Yang , Xiaobing Cai
Granular material is attracting increasing research momentum due to its prevalence and rich unique properties. Nevertheless, compared with its numerous functions in other areas, the application of granular material in acoustic waves has received less attention. In this paper, we propose that by exploiting Brazil-nut effect induced particle size segregation in granular material, a significant improvement in the sound absorption can be achieved. Firstly, sound absorptions by particles with step-increasing sizes have been analyzed. It is found that size-dependent mechanisms of sound energy dissipation may occur. Secondly, sound absorptions by size-mixed particles with vibration treatment have been studied. As a result of the Brazil-nut effect induced size segregation, the size-mixed particles with initially limited sound absorptivity exhibited remarkably improved sound absorbing capability, with both broadened absorbing band and raised low-frequency absorption. This work demonstrates that simple processing of the granular material may become a promising way to create premium sound absorbers.
{"title":"Improved sound absorption by size gradient granular materials due to Brazil-nut effect","authors":"Long Xu , Minglong Wang , Hui Li , Xiaozhen Li , Teng Wu , Chunguang Wang , Zhandong Huang , Peipei Jia , Jun Yang , Xiaobing Cai","doi":"10.1016/j.apacoust.2024.110416","DOIUrl":"10.1016/j.apacoust.2024.110416","url":null,"abstract":"<div><div>Granular material is attracting increasing research momentum due to its prevalence and rich unique properties. Nevertheless, compared with its numerous functions in other areas, the application of granular material in acoustic waves has received less attention. In this paper, we propose that by exploiting Brazil-nut effect induced particle size segregation in granular material, a significant improvement in the sound absorption can be achieved. Firstly, sound absorptions by particles with step-increasing sizes have been analyzed. It is found that size-dependent mechanisms of sound energy dissipation may occur. Secondly, sound absorptions by size-mixed particles with vibration treatment have been studied. As a result of the Brazil-nut effect induced size segregation, the size-mixed particles with initially limited sound absorptivity exhibited remarkably improved sound absorbing capability, with both broadened absorbing band and raised low-frequency absorption. This work demonstrates that simple processing of the granular material may become a promising way to create premium sound absorbers.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110416"},"PeriodicalIF":3.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1016/j.apacoust.2024.110424
Yunan Wang , Dingding Yao , Zhi Zhou , Daocheng Chen , Wenquan Feng , Junfeng Li
Spectral peaks and notches in the head-related transfer function (HRTF) are considered pivotal for elevation perception in virtual auditory displays (VAD), especially during static binaural signal playback. However, studies on dynamic binaural signal playback in VAD have shown that the auditory system can still utilize dynamic cues for elevation localization, even when these high-frequency spectral components are missing, although this may compromise localization accuracy. This study investigated the effects of spectral peaks and notches in dynamic playback, examining how distorting these features and their contrasts at various levels (33%, 66%, and 100% removal) influenced elevation localization along different rotational axes (yaw and pitch rotation). The results revealed that at the same distortion level, the impact of these features on median plane localization decreased sequentially from spectral contrast, to peaks, to notches. At a distortion level of 33%, notch removal enabled dynamic playback results that were not significantly different from control conditions. As distortion levels increased to 66% and 100%, localization performance progressively deteriorated, including increased localization errors and up-down confusion with head yaw rotation as well as front-back and up-down confusion with head pitch rotation. Simultaneously, localization performance with head pitch rotation exhibited poorer performance compared to yaw rotation, particularly in cases involving peak removal and contrast compression. The experimental results further revealed that auditory elevation localization benefits from multiple localization cues generated by head movements, including dynamic spectral cues produced during large head rotations when all spectral cues are available or distorted at a level of 33%.
{"title":"Effects of spectral peaks and notches in head-related transfer function on median plane sound localization with dynamic binaural playback","authors":"Yunan Wang , Dingding Yao , Zhi Zhou , Daocheng Chen , Wenquan Feng , Junfeng Li","doi":"10.1016/j.apacoust.2024.110424","DOIUrl":"10.1016/j.apacoust.2024.110424","url":null,"abstract":"<div><div>Spectral peaks and notches in the head-related transfer function (HRTF) are considered pivotal for elevation perception in virtual auditory displays (VAD), especially during static binaural signal playback. However, studies on dynamic binaural signal playback in VAD have shown that the auditory system can still utilize dynamic cues for elevation localization, even when these high-frequency spectral components are missing, although this may compromise localization accuracy. This study investigated the effects of spectral peaks and notches in dynamic playback, examining how distorting these features and their contrasts at various levels (33%, 66%, and 100% removal) influenced elevation localization along different rotational axes (yaw and pitch rotation). The results revealed that at the same distortion level, the impact of these features on median plane localization decreased sequentially from spectral contrast, to peaks, to notches. At a distortion level of 33%, notch removal enabled dynamic playback results that were not significantly different from control conditions. As distortion levels increased to 66% and 100%, localization performance progressively deteriorated, including increased localization errors and up-down confusion with head yaw rotation as well as front-back and up-down confusion with head pitch rotation. Simultaneously, localization performance with head pitch rotation exhibited poorer performance compared to yaw rotation, particularly in cases involving peak removal and contrast compression. The experimental results further revealed that auditory elevation localization benefits from multiple localization cues generated by head movements, including dynamic spectral cues produced during large head rotations when all spectral cues are available or distorted at a level of 33%.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"230 ","pages":"Article 110424"},"PeriodicalIF":3.4,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An omnidirectional parametric loudspeaker (OPL) is a sound source that relies on the parametric acoustic array (PAA) phenomenon to generate an omnidirectional sound field. It consists of hundreds of ultrasonic piezoelectric sensors placed on a sphere, each of which emits an ultrasonic carrier wave modulated in amplitude by an audible signal. Due to non-linear propagation in air, the audible signal is demodulated, resulting in an omnidirectional sound field consisting of audible and ultrasonic waves. Earlier work has shown that the OPL is more omnidirectional than a standard dodechaedron, although it produces lower sound pressure levels especially at lower frequencies. This sound source was originally designed for room acoustics, but its application to this field remains still unexplored. This paper proposes a method to measure the reverberation time of a room with an OPL using exponential sine sweeps (ESS). In addition, the sound absorption of material samples in a reverberation chamber is obtained. The results show that the OPL can measure these magnitudes with confidence, even though, compared to a standard dodechaedron, it has more difficulties in achieving large signal-to-noise ratios in the decay curves for the lower frequencies. The developed methodology also allows the ultrasonic frequency range to be examined. The results indicate that the ultrasonic waves do not penetrate the sample under test as they are attenuated during propagation in air.
{"title":"Reverberation time and random-incidence sound absorption measured in the audible and ultrasonic ranges with an omnidirectional parametric loudspeaker","authors":"Marc Arnela , Ricardo Burbano-Escolà , Rodrigo Scoczynski Ribeiro , Oriol Guasch","doi":"10.1016/j.apacoust.2024.110414","DOIUrl":"10.1016/j.apacoust.2024.110414","url":null,"abstract":"<div><div>An omnidirectional parametric loudspeaker (OPL) is a sound source that relies on the parametric acoustic array (PAA) phenomenon to generate an omnidirectional sound field. It consists of hundreds of ultrasonic piezoelectric sensors placed on a sphere, each of which emits an ultrasonic carrier wave modulated in amplitude by an audible signal. Due to non-linear propagation in air, the audible signal is demodulated, resulting in an omnidirectional sound field consisting of audible and ultrasonic waves. Earlier work has shown that the OPL is more omnidirectional than a standard dodechaedron, although it produces lower sound pressure levels especially at lower frequencies. This sound source was originally designed for room acoustics, but its application to this field remains still unexplored. This paper proposes a method to measure the reverberation time of a room with an OPL using exponential sine sweeps (ESS). In addition, the sound absorption of material samples in a reverberation chamber is obtained. The results show that the OPL can measure these magnitudes with confidence, even though, compared to a standard dodechaedron, it has more difficulties in achieving large signal-to-noise ratios in the decay curves for the lower frequencies. The developed methodology also allows the ultrasonic frequency range to be examined. The results indicate that the ultrasonic waves do not penetrate the sample under test as they are attenuated during propagation in air.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110414"},"PeriodicalIF":3.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.apacoust.2024.110391
Yanqi Wu , Huilin Xie , Yuebing Wang , Ben Wang , Huiyuan Cao
In focused ultrasound surgery (FUS) for tumour ablation, ensuring the safety and efficiency of the procedure is challenging. Currently, researchers are investigating the effects of bioparticles such as hydroxyapatite to improve the acoustic properties of the treatment region, aiming to increase tumour ablation efficiency. In this study, we aim to elucidate the intricate thermal effects of the visco-inertial transfer mechanisms between the nanoparticles and the surrounding tissue. We introduced a two-phase acoustic attenuation model to simulate the acoustic attenuation coefficient and temperature rise in tissue containing nanoparticles. The acoustic attenuation coefficient revealed a progressive increase in viscous losses, which can be converted into heat as the volume fraction of particles increases. A larger density difference between nanoparticles and surrounding tissue results in greater viscous losses. Moreover, when the particle radius falls within a specific range, the viscous losses reach the maximum values. The thermal accumulation analysis revealed that a medium containing particles ranging from tens of nanometres to one micrometre in size at a volume fraction of 1 %–3 % could achieve over twice the thermal accumulation efficiency of a pure medium. The experimental results of the biomimetic model, consistent with the numerical simulation results, indicate that the viscous heating effect is predominantly observed during the initial stage of irradiation, specifically within the first 5 s. These findings can contribute to improving treatment outcomes and expanding the applicability of FUS to different tumour types.
{"title":"Study of the viscous heating effect of particle enhancers in focused ultrasound based on the theory of two-phase media","authors":"Yanqi Wu , Huilin Xie , Yuebing Wang , Ben Wang , Huiyuan Cao","doi":"10.1016/j.apacoust.2024.110391","DOIUrl":"10.1016/j.apacoust.2024.110391","url":null,"abstract":"<div><div>In focused ultrasound surgery (FUS) for tumour ablation, ensuring the safety and efficiency of the procedure is challenging. Currently, researchers are investigating the effects of bioparticles such as hydroxyapatite to improve the acoustic properties of the treatment region, aiming to increase tumour ablation efficiency. In this study, we aim to elucidate the intricate thermal effects of the visco-inertial transfer mechanisms between the nanoparticles and the surrounding tissue. We introduced a two-phase acoustic attenuation model to simulate the acoustic attenuation coefficient and temperature rise in tissue containing nanoparticles. The acoustic attenuation coefficient revealed a progressive increase in viscous losses, which can be converted into heat as the volume fraction of particles increases. A larger density difference between nanoparticles and surrounding tissue results in greater viscous losses. Moreover, when the particle radius falls within a specific range, the viscous losses reach the maximum values. The thermal accumulation analysis revealed that a medium containing particles ranging from tens of nanometres to one micrometre in size at a volume fraction of 1 %–3 % could achieve over twice the thermal accumulation efficiency of a pure medium. The experimental results of the biomimetic model, consistent with the numerical simulation results, indicate that the viscous heating effect is predominantly observed during the initial stage of irradiation, specifically within the first 5 s. These findings can contribute to improving treatment outcomes and expanding the applicability of FUS to different tumour types.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110391"},"PeriodicalIF":3.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.apacoust.2024.110377
Li Zhang , Yao Chen , Yi-fan Dong , Xiao Yang , Xiao-gang Li , Wei Jiang , Ji-feng Tian , Ya-hong Wang , Ying Wang , Zhi-tong Ge , Xin Wang , Sheng Cai , Qing-li Zhu , Xiao-dong Han , Jian-chu Li
This study examines the reliability of subharmonic-aided pressure estimation (SHAPE) using polydisperse microbubbles. SHAPE utilizes the subharmonic response of ultrasound contrast agent microbubbles to estimate pressure non-invasively. Despite its potential, gaps in theoretical understanding and experimental inconsistencies with polydisperse microbubbles necessitate further investigation. This research explores the impact of microbubble distribution, excitation parameters, and contrast-enhanced ultrasound imaging modes on SHAPE’s signal consistency, measurement linearity, and sensitivity. A one-dimensional microbubble population model was developed to simulate microbubble behavior and the Hilbert transform demodulation technique was applied for subharmonic analyses. Variability in SHAPE was further assessed through flow phantom experiments using Sonazoid agents and a commercial SHAPE scanner. Findings indicate that bubble distribution in both size and location, microbubble interactions, and CEUS imaging modes significantly influence subharmonic responses. An excitation frequency of 3.5 MHz is recommended for robust SHAPE. Monte Carlo simulations confirmed the inherent variability of subharmonic amplitude signals due to dynamic bubble distributions. Using monodisperse microbubbles enhanced SHAPE sensitivity and consistency, without markedly reducing signal variability. These results underscore the necessity of further research to optimize SHAPE for clinical applications, focusing on microbubble characteristics and excitation conditions to enhance consistency and reliability.
{"title":"Towards reliable subharmonic-aided pressure estimation: Simulation and experimental validation of microbubble dynamics","authors":"Li Zhang , Yao Chen , Yi-fan Dong , Xiao Yang , Xiao-gang Li , Wei Jiang , Ji-feng Tian , Ya-hong Wang , Ying Wang , Zhi-tong Ge , Xin Wang , Sheng Cai , Qing-li Zhu , Xiao-dong Han , Jian-chu Li","doi":"10.1016/j.apacoust.2024.110377","DOIUrl":"10.1016/j.apacoust.2024.110377","url":null,"abstract":"<div><div>This study examines the reliability of subharmonic-aided pressure estimation (SHAPE) using polydisperse microbubbles. SHAPE utilizes the subharmonic response of ultrasound contrast agent microbubbles to estimate pressure non-invasively. Despite its potential, gaps in theoretical understanding and experimental inconsistencies with polydisperse microbubbles necessitate further investigation. This research explores the impact of microbubble distribution, excitation parameters, and contrast-enhanced ultrasound imaging modes on SHAPE’s signal consistency, measurement linearity, and sensitivity. A one-dimensional microbubble population model was developed to simulate microbubble behavior and the Hilbert transform demodulation technique was applied for subharmonic analyses. Variability in SHAPE was further assessed through flow phantom experiments using Sonazoid agents and a commercial SHAPE scanner. Findings indicate that bubble distribution in both size and location, microbubble interactions, and CEUS imaging modes significantly influence subharmonic responses. An excitation frequency of 3.5 MHz is recommended for robust SHAPE. Monte Carlo simulations confirmed the inherent variability of subharmonic amplitude signals due to dynamic bubble distributions. Using monodisperse microbubbles enhanced SHAPE sensitivity and consistency, without markedly reducing signal variability. These results underscore the necessity of further research to optimize SHAPE for clinical applications, focusing on microbubble characteristics and excitation conditions to enhance consistency and reliability.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110377"},"PeriodicalIF":3.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.apacoust.2024.110370
Fuka Nakamura , Kazuhiro Iida
It is known that notches and peaks at frequencies above 5 kHz in the head-related transfer function (HRTF) act as cues for median plane sound localization. However, it has also been shown that front-back discrimination of the direction of a sound image can be achieved even with only the components below 4 kHz. In the present study, we investigated the cues for rear sound image localization below 4 kHz. First, we analyzed the HRTFs for 118 ears (59 subjects) in the median plane and showed that the sound pressure around 1 kHz in the rear HRTF was larger than that in the front HRTF. This boosted band (hereinafter referred to as P0) coincided with Blauert’s directional band. Next, we proposed a hypothesis that can comprehensively explain the two types of cues that have been proposed in the past: spectral notches and peaks, and directional bands. In order to verify the effects of P0 for rear-direction localization, three preliminary psychoacoustic experiments were conducted. The results showed that eliminating P0 tends to increase localization errors at frequencies below 4 kHz. For wide-band signals, adding P0 to a previous parametric HRTF model (N1N2P1P2) tends to reduce the mean vertical localization error, and made the auditory source width approximately the same as that for the measured HRTF. These preliminary results support our hypothesis and imply that P0 acts as a cue for rear sound image localization.
{"title":"Cue for rear sound image localization in head-related transfer function below 4 kHz","authors":"Fuka Nakamura , Kazuhiro Iida","doi":"10.1016/j.apacoust.2024.110370","DOIUrl":"10.1016/j.apacoust.2024.110370","url":null,"abstract":"<div><div>It is known that notches and peaks at frequencies above 5 kHz in the head-related transfer function (HRTF) act as cues for median plane sound localization. However, it has also been shown that front-back discrimination of the direction of a sound image can be achieved even with only the components below 4 kHz. In the present study, we investigated the cues for rear sound image localization below 4 kHz. First, we analyzed the HRTFs for 118 ears (59 subjects) in the median plane and showed that the sound pressure around 1 kHz in the rear HRTF was larger than that in the front HRTF. This boosted band (hereinafter referred to as P0) coincided with Blauert’s directional band. Next, we proposed a hypothesis that can comprehensively explain the two types of cues that have been proposed in the past: spectral notches and peaks, and directional bands. In order to verify the effects of P0 for rear-direction localization, three preliminary psychoacoustic experiments were conducted. The results showed that eliminating P0 tends to increase localization errors at frequencies below 4 kHz. For wide-band signals, adding P0 to a previous parametric HRTF model (N1N2P1P2) tends to reduce the mean vertical localization error, and made the auditory source width approximately the same as that for the measured HRTF. These preliminary results support our hypothesis and imply that P0 acts as a cue for rear sound image localization.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110370"},"PeriodicalIF":3.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.apacoust.2024.110388
Yuanze Li, Linfeng Li, Lei Xiao, Li Cheng, Xiang Yu
The inherent conflict between natural ventilation and noise reduction presents a significant challenge in building design. To address this issue, double-layer ventilation windows have been developed, but their acoustic performance remains suboptimal when the window is partially open. Recently, sonic black hole (SBH) structures emerged as promising acoustic devices to absorb sound waves. This study explores the incorporation of SBH structures to enhance the acoustic performance of double-layer ventilation windows. The investigation focuses on positioning SBH units inside the window cavity for sound absorption, and at the outlet of the window for sound isolation. The working principles and modeling techniques for designing SBH units are elaborated. Impedance tube tests are conducted to confirm the desired sound absorption and transmission loss properties of the designed SBH elements under plane wave incidence conditions. To predict the acoustic performance of the modified windows, numerical models are developed using finite element analysis. The results indicate that the incorporation of SBH units yields improved sound attenuation within the target frequency range specified by the SBH design, and the design approach demonstrates great tunability and potential for optimization. To validate the numerical predictions, a 1:2 scale model of the window was constructed, with individual SBH elements produced via 3D printing. Experiments conducted in an anechoic chamber confirm the noise reduction capabilities of various window configurations with integrated SBH elements, and the experimental results corroborate well the numerical simulations. This study introduces the novel application of SBH in ventilation windows, with preliminary findings indicating the potential benefits of SBH integration. Further optimization based on the design approach, numerical models, and experimental techniques established herein is warranted.
{"title":"Enhancing ventilation window acoustics with sonic black hole integration: A performance evaluation","authors":"Yuanze Li, Linfeng Li, Lei Xiao, Li Cheng, Xiang Yu","doi":"10.1016/j.apacoust.2024.110388","DOIUrl":"10.1016/j.apacoust.2024.110388","url":null,"abstract":"<div><div>The inherent conflict between natural ventilation and noise reduction presents a significant challenge in building design. To address this issue, double-layer ventilation windows have been developed, but their acoustic performance remains suboptimal when the window is partially open. Recently, sonic black hole (SBH) structures emerged as promising acoustic devices to absorb sound waves. This study explores the incorporation of SBH structures to enhance the acoustic performance of double-layer ventilation windows. The investigation focuses on positioning SBH units inside the window cavity for sound absorption, and at the outlet of the window for sound isolation. The working principles and modeling techniques for designing SBH units are elaborated. Impedance tube tests are conducted to confirm the desired sound absorption and transmission loss properties of the designed SBH elements under plane wave incidence conditions. To predict the acoustic performance of the modified windows, numerical models are developed using finite element analysis. The results indicate that the incorporation of SBH units yields improved sound attenuation within the target frequency range specified by the SBH design, and the design approach demonstrates great tunability and potential for optimization. To validate the numerical predictions, a 1:2 scale model of the window was constructed, with individual SBH elements produced via 3D printing. Experiments conducted in an anechoic chamber confirm the noise reduction capabilities of various window configurations with integrated SBH elements, and the experimental results corroborate well the numerical simulations. This study introduces the novel application of SBH in ventilation windows, with preliminary findings indicating the potential benefits of SBH integration. Further optimization based on the design approach, numerical models, and experimental techniques established herein is warranted.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110388"},"PeriodicalIF":3.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1016/j.apacoust.2024.110392
Zhangming Zeng , Szu-Fu Huang , William N. Alexander , Anupam Sharma
A novel aerodynamic-whistle-based ultrasonic tone generator is proposed that has the potential to serve as a bat deterrent when installed on wind turbine rotor blades. The device uses blade-relative flow to excite resonance in cavities that are geometrically tailored to generate tones at the desired ultrasonic frequencies. A comprehensive experimental and numerical study is presented wherein two such deterrent designs are investigated. Experiments are performed in an anechoic wind tunnel where the deterrents are mounted on a blade section with the NACA 0012 profile. Measurements show that the deterrents produce the desired tonal spectrum when the tunnel flow speed exceeds a threshold value. There is also a maximum flow speed above which the deterrents do not generate tones. Variations with flow speed and blade angle of attack are investigated. Acoustic beamforming is used for source localization with partial success.
The compressible unsteady Reynolds-averaged Navier-Stokes equations are solved with the SST turbulence model to simulate the aeroacoustics of the deterrents. Two-dimensional simulations capture the tonal frequencies and the trends with flow speed and blade angle of attack observed in the experiments. Three-dimensional simulations are performed with span-periodic boundaries for two deterrent configurations – one with one resonator modeled and another with two resonators modeled. The flow unsteadiness is higher in the two-resonator configuration; however, the unsteady pressures in the two resonators are nearly out of phase. The Ffowcs Williams-Hawkings acoustic analogy is used to compute the far-field acoustics. The simulations capture the tonal sound pressure levels at the fundamental frequency and the second harmonic.
{"title":"A passive, blade-mounted ultrasonic bat deterrent for wind turbines","authors":"Zhangming Zeng , Szu-Fu Huang , William N. Alexander , Anupam Sharma","doi":"10.1016/j.apacoust.2024.110392","DOIUrl":"10.1016/j.apacoust.2024.110392","url":null,"abstract":"<div><div>A novel aerodynamic-whistle-based ultrasonic tone generator is proposed that has the potential to serve as a bat deterrent when installed on wind turbine rotor blades. The device uses blade-relative flow to excite resonance in cavities that are geometrically tailored to generate tones at the desired ultrasonic frequencies. A comprehensive experimental and numerical study is presented wherein two such deterrent designs are investigated. Experiments are performed in an anechoic wind tunnel where the deterrents are mounted on a blade section with the NACA 0012 profile. Measurements show that the deterrents produce the desired tonal spectrum when the tunnel flow speed exceeds a threshold value. There is also a maximum flow speed above which the deterrents do not generate tones. Variations with flow speed and blade angle of attack are investigated. Acoustic beamforming is used for source localization with partial success.</div><div>The compressible unsteady Reynolds-averaged Navier-Stokes equations are solved with the SST <span><math><mi>k</mi><mo>−</mo><mi>ω</mi></math></span> turbulence model to simulate the aeroacoustics of the deterrents. Two-dimensional simulations capture the tonal frequencies and the trends with flow speed and blade angle of attack observed in the experiments. Three-dimensional simulations are performed with span-periodic boundaries for two deterrent configurations – one with one resonator modeled and another with two resonators modeled. The flow unsteadiness is higher in the two-resonator configuration; however, the unsteady pressures in the two resonators are nearly out of phase. The Ffowcs Williams-Hawkings acoustic analogy is used to compute the far-field acoustics. The simulations capture the tonal sound pressure levels at the fundamental frequency and the second harmonic.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"229 ","pages":"Article 110392"},"PeriodicalIF":3.4,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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