Biography and scientific achievements of Academician Leonid Maksimovich Brekhovskikh - Russian physicist, the founder of the scientific school of Ocean Acoustics, Doctor of Physics and Mathematics Sciences, Professor, Academician of the Russian Academy of Sciences.
{"title":"Chronicle: Academician Leonid Maksimovich Brekhovskikh – 100th Anniversary of the Birth","authors":"A. Serebryany","doi":"10.24425/123926","DOIUrl":"https://doi.org/10.24425/123926","url":null,"abstract":"Biography and scientific achievements of Academician Leonid Maksimovich Brekhovskikh - Russian physicist, \u0000the founder of the scientific school of Ocean Acoustics, Doctor of Physics and Mathematics Sciences, Professor, Academician of the Russian Academy of Sciences.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46380578","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.2022.141659
{"title":"In Memoriam: Docent Janusz Renowski","authors":"","doi":"10.24425/aoa.2022.141659","DOIUrl":"https://doi.org/10.24425/aoa.2022.141659","url":null,"abstract":"","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45678058","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.2022.141653
Li Yuanwen, LI Min, Daofang Feng, Debin Yang, Long Wei
The microphone data collected in aeroacoustic wind tunnel test contains not only desired aeroacoustic signal but also background noise generated by the jet or the valve of the wind tunnel, so the desired aeroacoustic characteristics is difficult to be highlighted due to the low Signal-to-Noise Ratio (SNR). Classical cross spectral matrix removal can only reduce the microphone self-noise, but its effect is limited for jet noise. Therefore, an Airflow Background Noise Suppression method based on the Ensemble Empirical Mode Decomposition (ABNSEEMD) is proposed to eliminate the influence of background noise on aeroacoustic field reconstruction. The new method uses EEMD to adaptively separate the background noise in microphone data, which has good practicability for increasing SNR of aeroacoustic signal. A localization experiment was conducted by using two loudspeakers in wind tunnel with 80 m/s velocity. Results show that proposed method can filter out the background noise more effectively and improve the SNR of the loudspeakers signal compared with spectral subtraction and cepstrum methods. Moreover, the aeroacoustic field produced by a NACA EPPLER 862 STRUT airfoil model was also measured and reconstructed. Delay-and-sum beamforming maps of aeroacoustic source were displayed after the background noise was suppressed, which further demonstrates the proposed method’s advantage.
{"title":"Research on Airflow Background Noise Suppression for Aeroacoustic Wind Tunnel Testing","authors":"Li Yuanwen, LI Min, Daofang Feng, Debin Yang, Long Wei","doi":"10.24425/aoa.2022.141653","DOIUrl":"https://doi.org/10.24425/aoa.2022.141653","url":null,"abstract":"The microphone data collected in aeroacoustic wind tunnel test contains not only desired aeroacoustic signal but also background noise generated by the jet or the valve of the wind tunnel, so the desired aeroacoustic characteristics is difficult to be highlighted due to the low Signal-to-Noise Ratio (SNR). Classical cross spectral matrix removal can only reduce the microphone self-noise, but its effect is limited for jet noise. Therefore, an Airflow Background Noise Suppression method based on the Ensemble Empirical Mode Decomposition (ABNSEEMD) is proposed to eliminate the influence of background noise on aeroacoustic field reconstruction. The new method uses EEMD to adaptively separate the background noise in microphone data, which has good practicability for increasing SNR of aeroacoustic signal. A localization experiment was conducted by using two loudspeakers in wind tunnel with 80 m/s velocity. Results show that proposed method can filter out the background noise more effectively and improve the SNR of the loudspeakers signal compared with spectral subtraction and cepstrum methods. Moreover, the aeroacoustic field produced by a NACA EPPLER 862 STRUT airfoil model was also measured and reconstructed. Delay-and-sum beamforming maps of aeroacoustic source were displayed after the background noise was suppressed, which further demonstrates the proposed method’s advantage.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41547280","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.2020.132493
Ryszard Gubrynowicz
Krzysztof Marasek, lecturer and researcher at the Polish-Japanese Academy of Information Technology (PJAIT) and an expert at the National Information Processing Institute (OPI PIB) passed away on November 13, 2019. He was an outstanding scientist, an internationally acclaimed authority in the field of speech technology, an outstanding academic teacher and mentor to many scientists at home and abroad. Professor Krzysztof Marasek headed the PJAIT Multimedia Department created by him in 2002.
{"title":"In memoriam - prof. Krzysztof Marasek (1958–2019)","authors":"Ryszard Gubrynowicz","doi":"10.24425/AOA.2020.132493","DOIUrl":"https://doi.org/10.24425/AOA.2020.132493","url":null,"abstract":"Krzysztof Marasek, lecturer and researcher at the Polish-Japanese Academy of Information Technology (PJAIT) and an expert at the National Information Processing Institute (OPI PIB) passed away on November 13, 2019. He was an outstanding scientist, an internationally acclaimed authority in the field of speech technology, an outstanding academic teacher and mentor to many scientists at home and abroad. Professor Krzysztof Marasek headed the PJAIT Multimedia Department created by him in 2002.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41751372","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.2021.138155
Baljeet Singh, A. Sangwan, J. Singh
In this paper, we investigate a problem on reflection and transmission of plane-waves at an interface between two dissimilar half-spaces of a transversely isotropic micropolar piezoelectric material. The entire model is assumed to rotate with a uniform angular velocity. The governing equations of rotating and transversely isotropic micropolar piezoelectric medium are specialized in a plane. Plane-wave solutions of two-dimensional coupled governing equations show the possible propagation of three coupled plane-waves. For an incident plane-wave at an interface between two dissimilar half-spaces, three reflected and three transmitted waves propagate with distinct speeds. The connections between the amplitude ratios of reflected and transmitted waves are obtained. The expressions for the energy ratios of reflected and transmitted waves are also obtained. A numerical example of the present model is considered to illustrate the effects of rotation on the speeds and energy ratios graphically.
{"title":"Reflection and Transmission of Plane Wave at an Interface Between Two Rotating Micropolar Piezoelectric Solid Half-Spaces","authors":"Baljeet Singh, A. Sangwan, J. Singh","doi":"10.24425/aoa.2021.138155","DOIUrl":"https://doi.org/10.24425/aoa.2021.138155","url":null,"abstract":"In this paper, we investigate a problem on reflection and transmission of plane-waves at an interface between two dissimilar half-spaces of a transversely isotropic micropolar piezoelectric material. The entire model is assumed to rotate with a uniform angular velocity. The governing equations of rotating and transversely isotropic micropolar piezoelectric medium are specialized in a plane. Plane-wave solutions of two-dimensional coupled governing equations show the possible propagation of three coupled plane-waves. For an incident plane-wave at an interface between two dissimilar half-spaces, three reflected and three transmitted waves propagate with distinct speeds. The connections between the amplitude ratios of reflected and transmitted waves are obtained. The expressions for the energy ratios of reflected and transmitted waves are also obtained. A numerical example of the present model is considered to illustrate the effects of rotation on the speeds and energy ratios graphically.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44895010","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.2022.141644
S. Anjum, A. Kumari
Most of the Indian cities and towns have been facing serious traffic noise pollution due to urbanization, substantial growth of new vehicles, inadequate road network, etc. Automotive traffic, railroads, and air traffic are the most common sources of noise pollution in cities, with vehicular traffic accounting for around 55% of overall metropolitan noise. Prolonged exposure to such loud noise causes anger, stress, mental diseases, discomfort, hypertension, concentration problems, and sleeplessness. This study aims to investigate the effects of COVID-19 societal lockdown on changes in the noise pollution levels before, during, and after the lockdown period in various industrial, commercial, residential, and silence zones in Bengaluru, India, in light of the recent imposition of COVID-19 societal lockdown. According to data acquired from the KSPCB (Karnataka State Pollution Control Board) online portal, the average noise levels before and during lockdown were determined to be in the range of 59.4 dB to 70.9 dB and 58.2 dB to 62.7 dB for different zones. During the lockdown, all commercial, industrial and educational activities were closed to limit the spread of infection, resulting in usage of private and commercial transportation declining dramatically. Reduction in the noise level was observed during the lockdown in all monitoring stations of Bengaluru, except for Indira Gandhi Institute of Child Health, where the noise level didn???t decline because of a COVID emergency. Maximum reduction was observed in the commercial area (11.56%) followed by industrial areas (8.34%). The result further indicated that only the industrial area experienced an increase of 8.41% in noise level, while other areas experienced a reduction in a noise level during the early post-lockdown. During the mid and late post-lockdown periods, most locations experienced a rapid spike in the noise intensity.
{"title":"Evaluation of Noise Pollution in Bengaluru City, India During COVID-19 Pandemic","authors":"S. Anjum, A. Kumari","doi":"10.24425/aoa.2022.141644","DOIUrl":"https://doi.org/10.24425/aoa.2022.141644","url":null,"abstract":"Most of the Indian cities and towns have been facing serious traffic noise pollution due to urbanization, substantial growth of new vehicles, inadequate road network, etc. Automotive traffic, railroads, and air traffic are the most common sources of noise pollution in cities, with vehicular traffic accounting for around 55% of overall metropolitan noise. Prolonged exposure to such loud noise causes anger, stress, mental diseases, discomfort, hypertension, concentration problems, and sleeplessness. This study aims to investigate the effects of COVID-19 societal lockdown on changes in the noise pollution levels before, during, and after the lockdown period in various industrial, commercial, residential, and silence zones in Bengaluru, India, in light of the recent imposition of COVID-19 societal lockdown. According to data acquired from the KSPCB (Karnataka State Pollution Control Board) online portal, the average noise levels before and during lockdown were determined to be in the range of 59.4 dB to 70.9 dB and 58.2 dB to 62.7 dB for different zones. During the lockdown, all commercial, industrial and educational activities were closed to limit the spread of infection, resulting in usage of private and commercial transportation declining dramatically. Reduction in the noise level was observed during the lockdown in all monitoring stations of Bengaluru, except for Indira Gandhi Institute of Child Health, where the noise level didn???t decline because of a COVID emergency. Maximum reduction was observed in the commercial area (11.56%) followed by industrial areas (8.34%). The result further indicated that only the industrial area experienced an increase of 8.41% in noise level, while other areas experienced a reduction in a noise level during the early post-lockdown. During the mid and late post-lockdown periods, most locations experienced a rapid spike in the noise intensity.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45615736","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.2022.140737
Vattaparambil Sreedharan, Nachiketa Tiwari
Hydroacoustic projectors are useful for generating low frequency sounds in water. Existing works on hydroa-coustic projectors require two significant enhancements, especially for designers. First, we need to understand the influence of important projector design parameters on its performance. Such insights can be very useful in developing a compact and efficient projector. Second, there is a need for an integrated model of the projector based on easily available and user-friendly numerical tools which do not require development of complex customised mathematical analogs of projector components. The present work addresses both such needs. Towards these goals, an experimentally validated, easy-to-build projector model was developed and used to conduct design sensitivity studies. We show that reductions in pipe compliance and air content in oil, and an increase in orifice discharge coefficient can yield remarkable improvements in projector’s SPL. We also show that reductions in pipe length and cylinder diameter cause moderate improvements in performance in mass and stiffness controlled regions, respectively. In contrast, the projector performance is insensitive to changes in pistonic mass, cylinder length, and diaphragm stiffness. Finally, we report that while pipe compliance and air content in oil can sharply alter system resonance, the effects of changes in pipe length and pistonic mass on it are moderate in nature.
{"title":"Design Sensitivity Studies on a Hydroacoustic Projector Using an Experimentally Validated Easy-to-Build Model","authors":"Vattaparambil Sreedharan, Nachiketa Tiwari","doi":"10.24425/aoa.2022.140737","DOIUrl":"https://doi.org/10.24425/aoa.2022.140737","url":null,"abstract":"Hydroacoustic projectors are useful for generating low frequency sounds in water. Existing works on hydroa-coustic projectors require two significant enhancements, especially for designers. First, we need to understand the influence of important projector design parameters on its performance. Such insights can be very useful in developing a compact and efficient projector. Second, there is a need for an integrated model of the projector based on easily available and user-friendly numerical tools which do not require development of complex customised mathematical analogs of projector components. The present work addresses both such needs. Towards these goals, an experimentally validated, easy-to-build projector model was developed and used to conduct design sensitivity studies. We show that reductions in pipe compliance and air content in oil, and an increase in orifice discharge coefficient can yield remarkable improvements in projector’s SPL. We also show that reductions in pipe length and cylinder diameter cause moderate improvements in performance in mass and stiffness controlled regions, respectively. In contrast, the projector performance is insensitive to changes in pistonic mass, cylinder length, and diaphragm stiffness. Finally, we report that while pipe compliance and air content in oil can sharply alter system resonance, the effects of changes in pipe length and pistonic mass on it are moderate in nature.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46706886","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}
{"title":"47th Winter School on Wave and Quantum Acoustics XLVIth Winter School on Environmental Acoustics and Vibroacoustics Szczyrk, Poland, February 26 – March 1/2, 2018","authors":"F. Witos","doi":"10.24425/122381","DOIUrl":"https://doi.org/10.24425/122381","url":null,"abstract":"","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45174596","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}
{"title":"Professors Marianna Sankiewicz-Budzynski and Gustaw K.E. Budzynski Founders of the Polish Audio Engineering","authors":"A. Czyżewski, B. Kostek","doi":"10.24425/123907","DOIUrl":"https://doi.org/10.24425/123907","url":null,"abstract":"","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48024876","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.2022.142898
Lv Liang, Hu Kai, Fei Liu, L. Yawei, B. Cui
Cavitation has been widely used in wastewater degradation, material synthesis and biomedical field under dual-frequency acoustic excitation. The applications of cavitation are closely related to the power (i.e. the rate of internal energy accumulation) during bubble collapse. The Keller–Miksis equation considering liquid viscosity, surface tension and liquid compressibility is used to describe the radial motion of the bubble. The model is built in predicting the power during bubble collapse under dual-frequency acoustic excitation. The influences of parameters (i.e. phase difference, frequency difference, and amplitude ratio) on the power are investigated numerically. With the increase of phase difference, the power can be fluctuated in a wide range at all conditions. Three typical characteristics of the power appear under the effects of frequency difference and amplitude ratio. With the increase of amplitude ratio, if the frequency difference is small, the power has two maximum values; and if the frequency difference is medium, there is a maximum value. Otherwise, the power monotonously decreases. The results can provide theoretical references for the selections of experimental parameters of sono-luminescence and sonochemistry in the dual-frequency acoustic field.
{"title":"Energy analysis of cavitation bubbles under dual-frequency acoustic excitation","authors":"Lv Liang, Hu Kai, Fei Liu, L. Yawei, B. Cui","doi":"10.24425/aoa.2022.142898","DOIUrl":"https://doi.org/10.24425/aoa.2022.142898","url":null,"abstract":"Cavitation has been widely used in wastewater degradation, material synthesis and biomedical field under dual-frequency acoustic excitation. The applications of cavitation are closely related to the power (i.e. the rate of internal energy accumulation) during bubble collapse. The Keller–Miksis equation considering liquid viscosity, surface tension and liquid compressibility is used to describe the radial motion of the bubble. The model is built in predicting the power during bubble collapse under dual-frequency acoustic excitation. The influences of parameters (i.e. phase difference, frequency difference, and amplitude ratio) on the power are investigated numerically. With the increase of phase difference, the power can be fluctuated in a wide range at all conditions. Three typical characteristics of the power appear under the effects of frequency difference and amplitude ratio. With the increase of amplitude ratio, if the frequency difference is small, the power has two maximum values; and if the frequency difference is medium, there is a maximum value. Otherwise, the power monotonously decreases. The results can provide theoretical references for the selections of experimental parameters of sono-luminescence and sonochemistry in the dual-frequency acoustic field.","PeriodicalId":8149,"journal":{"name":"Archives of Acoustics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45055708","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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