Pub Date : 2023-07-20DOI: 10.24425/aoa.2022.140729
F. N. Gaafer
We theoretically propose a method to achieve an optimum absorbing material through a modulus-near-zero (MNZ) metamaterial immersed in air or water with a change in slit width part. The destructive interference has paved the way to achieve perfect absorption (PA). Depending upon theoretical analysis, an acoustic meta-material (AMMs) that supports resonance with a monopole (140 Hz) is developed to construct a low-frequency sound-absorbing technology. The dissipative loss effect can be by attentively controlling onto slit width to achieve perfect absorption. When there are thin slit width and visco-thermal losses in the structure, it is observed that they lead to high absorption. We use finite element simulations via COMSOL Multiphysics software to theoretical measurement in impedance tube and show the influence of structural parameters in both me-diums. The results are of extraordinary correspondence at low frequency to achieve optimum perfect absorption (99%). That might support AMMs to actual engineering-related applications in the process of mitigating noise, slow sound trapping
{"title":"Perfect Absorption for Modulus-Near-Zero Acoustic Metamaterial in Air or Underwater at Low-Frequency","authors":"F. N. Gaafer","doi":"10.24425/aoa.2022.140729","DOIUrl":"https://doi.org/10.24425/aoa.2022.140729","url":null,"abstract":"We theoretically propose a method to achieve an optimum absorbing material through a modulus-near-zero (MNZ) metamaterial immersed in air or water with a change in slit width part. The destructive interference has paved the way to achieve perfect absorption (PA). Depending upon theoretical analysis, an acoustic meta-material (AMMs) that supports resonance with a monopole (140 Hz) is developed to construct a low-frequency sound-absorbing technology. The dissipative loss effect can be by attentively controlling onto slit width to achieve perfect absorption. When there are thin slit width and visco-thermal losses in the structure, it is observed that they lead to high absorption. We use finite element simulations via COMSOL Multiphysics software to theoretical measurement in impedance tube and show the influence of structural parameters in both me-diums. The results are of extraordinary correspondence at low frequency to achieve optimum perfect absorption (99%). That might support AMMs to actual engineering-related applications in the process of mitigating noise, slow sound trapping","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49024574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2022.141646
M. Wajid, Arun Kumar
.
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{"title":"Microphone Based Acoustic Vector Sensor for Direction Finding with Bias Removal","authors":"M. Wajid, Arun Kumar","doi":"10.24425/aoa.2022.141646","DOIUrl":"https://doi.org/10.24425/aoa.2022.141646","url":null,"abstract":".","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48501953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2022.142012
Meng-Lun Hsueh, Jin-Peng Chen, LU Bing-Yuh, Wu Huey-Dong, Pei-Yi Liu
A moving average (MA) is a commonly used noise reduction method in signal processing. Several studies on wheeze auscultation have used MA analysis for preprocessing. The present study compared the performance of MA analysis with that of differential operation (DO) by observing the produced spectrograms. These signal preprocessing methods are not only applicable to wheeze signals but also to signals produced by systems such as machines, cars, and flows. Accordingly, this comparison is relevant in various fields. The results revealed that DO increased the signal power intensity of episodes in the spectrograms by more than 10 dB in terms of the signal-to-noise ratio (SNR). A mathematical analysis of relevant equations demonstrated that DO could identify high-frequency episodes in an input signal. Compared with a two-dimensional Laplacian operation, the DO method is easier to implement and could be used in other studies on acoustic signal processing. DO achieved high performance not only in denoising but also in enhancing wheeze signal features. The spectrograms revealed episodes at the fourth or even fifth harmonics; thus, DO can identify high-frequency episodes. In conclusion, MA reduces noise and DO enhances episodes in the high-frequency range; combining these methods enables efficient signal preprocessing for spectrograms.
{"title":"Comparison of Moving Average and Differential Operation for Wheeze Detection in Spectrograms","authors":"Meng-Lun Hsueh, Jin-Peng Chen, LU Bing-Yuh, Wu Huey-Dong, Pei-Yi Liu","doi":"10.24425/aoa.2022.142012","DOIUrl":"https://doi.org/10.24425/aoa.2022.142012","url":null,"abstract":"A moving average (MA) is a commonly used noise reduction method in signal processing. Several studies on wheeze auscultation have used MA analysis for preprocessing. The present study compared the performance of MA analysis with that of differential operation (DO) by observing the produced spectrograms. These signal preprocessing methods are not only applicable to wheeze signals but also to signals produced by systems such as machines, cars, and flows. Accordingly, this comparison is relevant in various fields. The results revealed that DO increased the signal power intensity of episodes in the spectrograms by more than 10 dB in terms of the signal-to-noise ratio (SNR). A mathematical analysis of relevant equations demonstrated that DO could identify high-frequency episodes in an input signal. Compared with a two-dimensional Laplacian operation, the DO method is easier to implement and could be used in other studies on acoustic signal processing. DO achieved high performance not only in denoising but also in enhancing wheeze signal features. The spectrograms revealed episodes at the fourth or even fifth harmonics; thus, DO can identify high-frequency episodes. In conclusion, MA reduces noise and DO enhances episodes in the high-frequency range; combining these methods enables efficient signal preprocessing for spectrograms.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48797273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2022.142900
Bo Zhao, Li He
In the calculation of the acoustic performance of mufflers, the walls of mufflers are usually treated rigidly without considering the acoustic-structural coupling, but the results so calculated differ significantly from the actual situation. Based on the basic equations, the article derives the finite element equations of the muf-fler system while considering the acoustic-structural coupling effect and theoretically analyses the connection between the acoustic-structural coupling system and the structural and acoustic modes. The structural and acoustic modes of the muffler are calculated and the reasons for the mutation of the transmission loss curve of the muffler when the acoustic-structural coupling is considered are analysed. The results show that the acoustic-structural coupling is the result of the interaction between the structure and the air inside the expansion chamber under acoustic excitation, which manifests mutations in the sound pressure inside the muffler in some frequency bands. Then, using a single-chamber muffler as an example, the transmission loss is used to characterise the performance of the muffler. The effects of different factors such as shell thickness, structure, porous media material lining, and restraint method on the acoustic-structural coupling effect of the muffler are analysed, and the structure of a double-chamber muffler is successfully optimised according to the conclusions.
{"title":"Analysis of the influencing factors of the acoustic performance of the muffler considering acoustic structural coupling","authors":"Bo Zhao, Li He","doi":"10.24425/aoa.2022.142900","DOIUrl":"https://doi.org/10.24425/aoa.2022.142900","url":null,"abstract":"In the calculation of the acoustic performance of mufflers, the walls of mufflers are usually treated rigidly without considering the acoustic-structural coupling, but the results so calculated differ significantly from the actual situation. Based on the basic equations, the article derives the finite element equations of the muf-fler system while considering the acoustic-structural coupling effect and theoretically analyses the connection between the acoustic-structural coupling system and the structural and acoustic modes. The structural and acoustic modes of the muffler are calculated and the reasons for the mutation of the transmission loss curve of the muffler when the acoustic-structural coupling is considered are analysed. The results show that the acoustic-structural coupling is the result of the interaction between the structure and the air inside the expansion chamber under acoustic excitation, which manifests mutations in the sound pressure inside the muffler in some frequency bands. Then, using a single-chamber muffler as an example, the transmission loss is used to characterise the performance of the muffler. The effects of different factors such as shell thickness, structure, porous media material lining, and restraint method on the acoustic-structural coupling effect of the muffler are analysed, and the structure of a double-chamber muffler is successfully optimised according to the conclusions.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68945470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2023.144266
{"title":"Evaluation of the Effect of Uncertainties on the Acoustic Behavior of a Porous Material Located in a Duct Element Using the Monte Carlo Method","authors":"","doi":"10.24425/aoa.2023.144266","DOIUrl":"https://doi.org/10.24425/aoa.2023.144266","url":null,"abstract":"","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45787853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2022.142907
RI Kyong-Su, Myong-jin Kim
In this paper, we present one approach to improve the soundproofing performance of the double-panel structure (DPS) in the entire audible frequencies, in which two kinds of local resonances, the breathing-type resonance and the Helmholtz resonance, are combined. The thin ring resonator row and slit-type resonator (Helmholtz resonator) row are inserted between two panels of DPS together. Overlapping of the band gaps due to the individual resonances gives a wide and high band gap of sound transmission in the low frequency range. At the same time, the Bragg-type band gap is created by the structural periodicity of the scatterers in the high audible frequency range. In addition, the number of scatterer rows and the filling factor are investigated with regard to the sound insulation of DPS with sonic crystals (SCs). Consequently, the hybrid SC has the potential of increasing the soundproofing performance of DPS in the audible frequency range above 1 kHz by about 15 dB on average compared to DPS filled only with glass wool between two panels, while decreasing the total thickness and mass compared to the counterparts with the other type of local resonant sonic crystal.
{"title":"Improvement of Sound Insulation Through Double-Panel Structure by Using Hybrid Local Resonator Array","authors":"RI Kyong-Su, Myong-jin Kim","doi":"10.24425/aoa.2022.142907","DOIUrl":"https://doi.org/10.24425/aoa.2022.142907","url":null,"abstract":"In this paper, we present one approach to improve the soundproofing performance of the double-panel structure (DPS) in the entire audible frequencies, in which two kinds of local resonances, the breathing-type resonance and the Helmholtz resonance, are combined. The thin ring resonator row and slit-type resonator (Helmholtz resonator) row are inserted between two panels of DPS together. Overlapping of the band gaps due to the individual resonances gives a wide and high band gap of sound transmission in the low frequency range. At the same time, the Bragg-type band gap is created by the structural periodicity of the scatterers in the high audible frequency range. In addition, the number of scatterer rows and the filling factor are investigated with regard to the sound insulation of DPS with sonic crystals (SCs). Consequently, the hybrid SC has the potential of increasing the soundproofing performance of DPS in the audible frequency range above 1 kHz by about 15 dB on average compared to DPS filled only with glass wool between two panels, while decreasing the total thickness and mass compared to the counterparts with the other type of local resonant sonic crystal.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42541175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2022.142902
{"title":"Professor Józef Lewandowski","authors":"","doi":"10.24425/aoa.2022.142902","DOIUrl":"https://doi.org/10.24425/aoa.2022.142902","url":null,"abstract":"","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47981994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2022.141652
D. Tounsi, W. Taktak, R. Dhief, M. Haddar
Duct silencers provide effective noise reduction for heating, ventilation and air conditioning systems. These silencers can achieve an excellent sound attenuation through the attributes of their design. The reactive silencer works on the principle of high reflection of sound waves at low frequencies. On the other hand, the dissipative silencer works on the principle of sound absorption, which is very effective at high-frequencies. Combining these two kinds of silencers allowed covering the whole frequency range. In this paper, the effect of liner characteristics composed of a perforated plate backed by a porous material and geometry discontinuities on the acoustic power attenuation of lined ducts is evaluated. This objective is achieved by using a numerical model to compute the multimodal scattering matrix, thus allowing deducing the acoustic power attenuation. The numerical results are obtained for six configurations, including cases of narrowing and widening of a radius duct with sudden or progressive discontinuities. Numerical acoustic power attenuation shows the relative influence of the variation in the values of each parameter of the liner, and of each type of radius discontinuities of ducts.
{"title":"Evaluation of the Acoustic Performance of Porous Materials Lined Ducts with Geometric Discontinuities","authors":"D. Tounsi, W. Taktak, R. Dhief, M. Haddar","doi":"10.24425/aoa.2022.141652","DOIUrl":"https://doi.org/10.24425/aoa.2022.141652","url":null,"abstract":"Duct silencers provide effective noise reduction for heating, ventilation and air conditioning systems. These silencers can achieve an excellent sound attenuation through the attributes of their design. The reactive silencer works on the principle of high reflection of sound waves at low frequencies. On the other hand, the dissipative silencer works on the principle of sound absorption, which is very effective at high-frequencies. Combining these two kinds of silencers allowed covering the whole frequency range. In this paper, the effect of liner characteristics composed of a perforated plate backed by a porous material and geometry discontinuities on the acoustic power attenuation of lined ducts is evaluated. This objective is achieved by using a numerical model to compute the multimodal scattering matrix, thus allowing deducing the acoustic power attenuation. The numerical results are obtained for six configurations, including cases of narrowing and widening of a radius duct with sudden or progressive discontinuities. Numerical acoustic power attenuation shows the relative influence of the variation in the values of each parameter of the liner, and of each type of radius discontinuities of ducts.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42933707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-07-20DOI: 10.24425/aoa.2021.139646
Paweł, K. Anna, Jędrzej, Adam
4th order ambisonic microphone in acoustic field analysis
声场分析中的四阶双声传声器
{"title":"67th Open Seminar on Acoustics September 14 – 17, 2021","authors":"Paweł, K. Anna, Jędrzej, Adam","doi":"10.24425/aoa.2021.139646","DOIUrl":"https://doi.org/10.24425/aoa.2021.139646","url":null,"abstract":"4th order ambisonic microphone in acoustic field analysis","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44493772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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