C. Lavandier, Mehdi Regragui, Romain Dedieu, C. Royer, A. Can
The influence of fluctuating road traffic noise on perceived disturbance during a reading task as well as on performance, inside a living room with closed windows, is presented in this paper. Sixteen 2-min sound sequences were created combining two variables: the number of events (four levels varying from one to four car pass-bys) and the peak emergence above the background noise (four levels with a 5 dB(A) step) keeping limited variations of LAmax, 1s. The noise impact was evaluated through a reading task of texts synchronized with the sound sequences, for participants classified into fast or slow readers, and sensitive or non-sensitive to noise. The comprehension rate of the texts decreases as the background sound level increases. The reading speed decreases during the rising front of a peak, and goes back to its former regular reading speed during the descending front of the peak. This slowdown during the rising front reaches 14% for slow readers. The declared disturbance is higher for slow readers compared to fast readers, and higher for noise sensitive persons compared to non-sensitive persons. The influence of the acoustic indicators on the reading disturbance is very small compared to the influence of personal factors. There is even no influence of the number of events on this disturbance.
{"title":"Influence of road traffic noise peaks on reading task performance and disturbance in a laboratory context","authors":"C. Lavandier, Mehdi Regragui, Romain Dedieu, C. Royer, A. Can","doi":"10.1051/aacus/2021057","DOIUrl":"https://doi.org/10.1051/aacus/2021057","url":null,"abstract":"The influence of fluctuating road traffic noise on perceived disturbance during a reading task as well as on performance, inside a living room with closed windows, is presented in this paper. Sixteen 2-min sound sequences were created combining two variables: the number of events (four levels varying from one to four car pass-bys) and the peak emergence above the background noise (four levels with a 5 dB(A) step) keeping limited variations of LAmax, 1s. The noise impact was evaluated through a reading task of texts synchronized with the sound sequences, for participants classified into fast or slow readers, and sensitive or non-sensitive to noise. The comprehension rate of the texts decreases as the background sound level increases. The reading speed decreases during the rising front of a peak, and goes back to its former regular reading speed during the descending front of the peak. This slowdown during the rising front reaches 14% for slow readers. The declared disturbance is higher for slow readers compared to fast readers, and higher for noise sensitive persons compared to non-sensitive persons. The influence of the acoustic indicators on the reading disturbance is very small compared to the influence of personal factors. There is even no influence of the number of events on this disturbance.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"17 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89034790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Binaural rendering of Ambisonics signals is a common way to reproduce spatial audio content. Processing Ambisonics signals at low spatial orders is desirable in order to reduce complexity, although it may degrade the perceived quality, in part due to the mismatch that occurs when a low-order Ambisonics signal is paired with a spatially dense head-related transfer function (HRTF). In order to alleviate this issue, the HRTF may be preprocessed so its spatial order is reduced. Several preprocessing methods have been proposed, but they have not been thoroughly compared yet. In this study, nine HRTF preprocessing methods were used to render anechoic binaural signals from Ambisonics representations of orders 1 to 44, and these were compared through perceptual hearing models in terms of localisation performance, externalisation and speech reception. This assessment was supported by numerical analyses of HRTF interpolation errors, interaural differences, perceptually-relevant spectral differences, and loudness stability. Models predicted that the binaural renderings’ accuracy increased with spatial order, as expected. A notable effect of the preprocessing method was observed: whereas all methods performed similarly at the highest spatial orders, some were considerably better at lower orders. A newly proposed method, BiMagLS, displayed the best performance overall and is recommended for the rendering of bilateral Ambisonics signals. The results, which were in line with previous literature, indirectly validate the perceptual models’ ability to predict listeners’ responses in a consistent and explicable manner.
{"title":"Assessing HRTF preprocessing methods for Ambisonics rendering through perceptual models","authors":"Isaac Engel, Dan F. M. Goodman, L. Picinali","doi":"10.1051/aacus/2021055","DOIUrl":"https://doi.org/10.1051/aacus/2021055","url":null,"abstract":"Binaural rendering of Ambisonics signals is a common way to reproduce spatial audio content. Processing Ambisonics signals at low spatial orders is desirable in order to reduce complexity, although it may degrade the perceived quality, in part due to the mismatch that occurs when a low-order Ambisonics signal is paired with a spatially dense head-related transfer function (HRTF). In order to alleviate this issue, the HRTF may be preprocessed so its spatial order is reduced. Several preprocessing methods have been proposed, but they have not been thoroughly compared yet. In this study, nine HRTF preprocessing methods were used to render anechoic binaural signals from Ambisonics representations of orders 1 to 44, and these were compared through perceptual hearing models in terms of localisation performance, externalisation and speech reception. This assessment was supported by numerical analyses of HRTF interpolation errors, interaural differences, perceptually-relevant spectral differences, and loudness stability. Models predicted that the binaural renderings’ accuracy increased with spatial order, as expected. A notable effect of the preprocessing method was observed: whereas all methods performed similarly at the highest spatial orders, some were considerably better at lower orders. A newly proposed method, BiMagLS, displayed the best performance overall and is recommended for the rendering of bilateral Ambisonics signals. The results, which were in line with previous literature, indirectly validate the perceptual models’ ability to predict listeners’ responses in a consistent and explicable manner.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"14 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81921371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The design of pianos is mainly based on empirical knowledge due to the lack of a simple tool that could predict sound changes induced by modifications of the geometry and/or the mechanical properties of the soundboard. We introduce the concept of Sound Computer-Aided Design through the framework of a program that is intended to simulate the acoustic results of virtual pianos. The calculation of the sound is split into four modules that compute respectively the modal basis of the stiffened soundboard, the string dynamics excited by the hammer, the soundboard dynamics excited by the string vibration, and the sound radiation. The exact resemblance between synthesis and natural sounds is not the primary purpose of the software. However, sound synthesis of real and modified pianos are used as reference tests to assess our main objective, namely to reflect faithfully structural modifications in the produced sound, and thus to make this tool helpful for both instrument makers and researchers of the musical acoustics community.
{"title":"Physically-based sound synthesis software for Computer-Aided-Design of piano soundboards","authors":"Benjamin Elie, B. Cotté, X. Boutillon","doi":"10.1051/aacus/2022024","DOIUrl":"https://doi.org/10.1051/aacus/2022024","url":null,"abstract":"The design of pianos is mainly based on empirical knowledge due to the lack of a simple tool that could predict sound changes induced by modifications of the geometry and/or the mechanical properties of the soundboard. We introduce the concept of Sound Computer-Aided Design through the framework of a program that is intended to simulate the acoustic results of virtual pianos. The calculation of the sound is split into four modules that compute respectively the modal basis of the stiffened soundboard, the string dynamics excited by the hammer, the soundboard dynamics excited by the string vibration, and the sound radiation. The exact resemblance between synthesis and natural sounds is not the primary purpose of the software. However, sound synthesis of real and modified pianos are used as reference tests to assess our main objective, namely to reflect faithfully structural modifications in the produced sound, and thus to make this tool helpful for both instrument makers and researchers of the musical acoustics community.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"11 14 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81030190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The tonal noise generated at the tip is a major contribution to the aerodynamic noise generated by three-dimensional airfoils. One way to reduce this noise is the use of end plates, which was investigated in the present study for three different circular end plate geometries applied to a cambered NACA 4412 airfoil with aspect ratio 2 and forced boundary layer transition. Microphone array measurements were performed in a small aeroacoustic wind tunnel for chord based Reynolds numbers between 75,000 and 200,000 and geometric angles of attack between 0° and 20°. The acoustic far-field noise spectra obtained for the baseline configuration show a broadband hump centered at a chord based Strouhal number of 13 that is associated with the noise generation at the tip and scales with the third power of the flow velocity. The application of end plates reduces this peak and is most effective for end plates which bound the flow on the suction side of the airfoil. Hot-wire measurements taken for one configuration show that the end plates diffuse the turbulence intensity in the relevant frequency range and reduce the fluid transfer along the pressure gradient at the tip. The suction side end plate additionally prevents the interaction of turbulent structures with the trailing edge and is therefore more effective in reducing noise. Surface flow visualizations for this configuration reveal a separation line extending along the full span up to the tip while the surface flow of the baseline and pressure configuration is strongly affected by the flow swept around the tip. Therefore, the placement of the end plate on the suction side is more effective in reducing tip noise.
{"title":"Influence of end plate placement on the reduction of airfoil tip vortex formation noise","authors":"Erik W. Schneehagen, T. Geyer, E. Sarradj","doi":"10.1051/aacus/2022053","DOIUrl":"https://doi.org/10.1051/aacus/2022053","url":null,"abstract":"The tonal noise generated at the tip is a major contribution to the aerodynamic noise generated by three-dimensional airfoils. One way to reduce this noise is the use of end plates, which was investigated in the present study for three different circular end plate geometries applied to a cambered NACA 4412 airfoil with aspect ratio 2 and forced boundary layer transition. Microphone array measurements were performed in a small aeroacoustic wind tunnel for chord based Reynolds numbers between 75,000 and 200,000 and geometric angles of attack between 0° and 20°. The acoustic far-field noise spectra obtained for the baseline configuration show a broadband hump centered at a chord based Strouhal number of 13 that is associated with the noise generation at the tip and scales with the third power of the flow velocity. The application of end plates reduces this peak and is most effective for end plates which bound the flow on the suction side of the airfoil. Hot-wire measurements taken for one configuration show that the end plates diffuse the turbulence intensity in the relevant frequency range and reduce the fluid transfer along the pressure gradient at the tip. The suction side end plate additionally prevents the interaction of turbulent structures with the trailing edge and is therefore more effective in reducing noise. Surface flow visualizations for this configuration reveal a separation line extending along the full span up to the tip while the surface flow of the baseline and pressure configuration is strongly affected by the flow swept around the tip. Therefore, the placement of the end plate on the suction side is more effective in reducing tip noise.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"46 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84106992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The presence and properties of acoustic peaks near the nozzle of impinging rocket jets have been investigated. Four jets at a Mach number of 3.1 impinging on a plate at a distance L = 15r0, 20r0, 25r0 and 30r0 from the nozzle, where r0 is the nozzle radius, have been computed using large-eddy simulations. In all cases, upstream-travelling pressure waves are generated by the jet impingement on the plate, with amplitudes decreasing with the nozzle-to-plate distance. The near-nozzle pressure spectra contain peaks, at frequencies not varying much with this distance. For L ≥ 20r0, the spectra are dominated by a low-frequency peak, whereas two additional high-frequency peaks emerge for L = 15r0. The low-frequency peak is associated with the azimuthal mode nθ = 0, whereas the two other ones are due to strong components for modes nθ ≥ 1. As for near-nozzle tones for free and impinging jets at lower Mach numbers, the peak frequencies fall close to the frequency bands of the upstream-propagating guided jet waves, showing a link between the peaks and the latter waves. Regarding the peak levels, they do not change significantly with the nozzle-to-plate distance for the low-frequency peak, but they decrease by 1.5 to 18 dB as the distance increases for the other peaks. Finally, for L ≥ 20r0, the near-nozzle peak frequency is close to that of the strongest shear-layer structures, indicating a connexion between the upstream noise and these structures. For L = 15r0, a shock-leakage mechanism of a near-plate shock is found to generate the upstream noise.
{"title":"Presence and properties of acoustic peaks near the nozzle of impinging rocket jets","authors":"Mathieu Varé, C. Bogey","doi":"10.1051/aacus/2022033","DOIUrl":"https://doi.org/10.1051/aacus/2022033","url":null,"abstract":"The presence and properties of acoustic peaks near the nozzle of impinging rocket jets have been investigated. Four jets at a Mach number of 3.1 impinging on a plate at a distance L = 15r0, 20r0, 25r0 and 30r0 from the nozzle, where r0 is the nozzle radius, have been computed using large-eddy simulations. In all cases, upstream-travelling pressure waves are generated by the jet impingement on the plate, with amplitudes decreasing with the nozzle-to-plate distance. The near-nozzle pressure spectra contain peaks, at frequencies not varying much with this distance. For L ≥ 20r0, the spectra are dominated by a low-frequency peak, whereas two additional high-frequency peaks emerge for L = 15r0. The low-frequency peak is associated with the azimuthal mode nθ = 0, whereas the two other ones are due to strong components for modes nθ ≥ 1. As for near-nozzle tones for free and impinging jets at lower Mach numbers, the peak frequencies fall close to the frequency bands of the upstream-propagating guided jet waves, showing a link between the peaks and the latter waves. Regarding the peak levels, they do not change significantly with the nozzle-to-plate distance for the low-frequency peak, but they decrease by 1.5 to 18 dB as the distance increases for the other peaks. Finally, for L ≥ 20r0, the near-nozzle peak frequency is close to that of the strongest shear-layer structures, indicating a connexion between the upstream noise and these structures. For L = 15r0, a shock-leakage mechanism of a near-plate shock is found to generate the upstream noise.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"208 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76429314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
M. Majnooni, E. Doveri, Jeanne Baldisser, V. Long, J. Houles, J. Scimeca, D. Momier, C. Guivier-Curien, P. Lasaygues, C. Baron
Low-intensity ultrasound stimulation is a technique used in therapeutic ultrasound for bone regeneration. However, the underlying mechanisms are still poorly understood. In vitro studies on cell cultures are implemented to understand the processes involved. To analyze the effects of ultrasonic waves on cells, the control of the delivered acoustic intensity is essential. However, depending on the insonification protocol chosen, multiple reflections and standing waves that form inside the culture medium strongly hinder the estimates. In this work, we propose the development and the experimental validation of an anti-reflection cover. We demonstrate that this custom-designed device is effective in avoiding multiple reflections and makes it possible to artificially replace the layer of culture medium with a large amount of water. Finally, an analytical study of the acoustic intensity delivered to the cells is proposed.
{"title":"Anti-reflection cover to control acoustic intensity in in vitro low-intensity ultrasound stimulation of cells","authors":"M. Majnooni, E. Doveri, Jeanne Baldisser, V. Long, J. Houles, J. Scimeca, D. Momier, C. Guivier-Curien, P. Lasaygues, C. Baron","doi":"10.1051/aacus/2022007","DOIUrl":"https://doi.org/10.1051/aacus/2022007","url":null,"abstract":"Low-intensity ultrasound stimulation is a technique used in therapeutic ultrasound for bone regeneration. However, the underlying mechanisms are still poorly understood. In vitro studies on cell cultures are implemented to understand the processes involved. To analyze the effects of ultrasonic waves on cells, the control of the delivered acoustic intensity is essential. However, depending on the insonification protocol chosen, multiple reflections and standing waves that form inside the culture medium strongly hinder the estimates. In this work, we propose the development and the experimental validation of an anti-reflection cover. We demonstrate that this custom-designed device is effective in avoiding multiple reflections and makes it possible to artificially replace the layer of culture medium with a large amount of water. Finally, an analytical study of the acoustic intensity delivered to the cells is proposed.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"60 2 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79765844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Recently, exploring acoustic conditions of people in their everyday environments has drawn a lot of attention. One of the most important and disturbing sound sources is the test participant’s own voice. This contribution proposes an algorithm to determine the own-voice audio segments (OVS) for blocks of 125 ms and a method for measuring sound pressure levels (SPL) without violating privacy laws. The own voice detection (OVD) algorithm here developed is based on a machine learning algorithm and a set of acoustic features that do not allow for speech reconstruction. A manually labeled real-world recording of one full day showed reliable and robust detection results. Moreover, the OVD algorithm was applied to 13 near-ear recordings of hearing-impaired participants in an ecological momentary assessment (EMA) study. The analysis shows that the grand mean percentage of predicted OVS during one day was approx. 10% which corresponds well to other published data. These OVS had a small impact on the median SPL over all data. However, for short analysis intervals, significant differences up to 30 dB occurred in the measured SPL, depending on the proportion of OVS and the SPL of the background noise.
{"title":"Near-ear sound pressure level distribution in everyday life considering the user’s own voice and privacy","authors":"Jule Pohlhausen, I. Holube, J. Bitzer","doi":"10.1051/aacus/2022035","DOIUrl":"https://doi.org/10.1051/aacus/2022035","url":null,"abstract":"Recently, exploring acoustic conditions of people in their everyday environments has drawn a lot of attention. One of the most important and disturbing sound sources is the test participant’s own voice. This contribution proposes an algorithm to determine the own-voice audio segments (OVS) for blocks of 125 ms and a method for measuring sound pressure levels (SPL) without violating privacy laws. The own voice detection (OVD) algorithm here developed is based on a machine learning algorithm and a set of acoustic features that do not allow for speech reconstruction. A manually labeled real-world recording of one full day showed reliable and robust detection results. Moreover, the OVD algorithm was applied to 13 near-ear recordings of hearing-impaired participants in an ecological momentary assessment (EMA) study. The analysis shows that the grand mean percentage of predicted OVS during one day was approx. 10% which corresponds well to other published data. These OVS had a small impact on the median SPL over all data. However, for short analysis intervals, significant differences up to 30 dB occurred in the measured SPL, depending on the proportion of OVS and the SPL of the background noise.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"6 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79161317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
S. Dupont, Maryna Sanalatii, M. Melon, O. Robin, A. Berry, J. Le Roux
Standardized methods for measuring sound absorption such as the impedance tube and reverberation chamber methods are limited to normal or diffuse incidence, respectively. Two research axes have been generally followed in the literature to develop alternative techniques, the first one focusing on the measurement part, that is from the two-microphone technique to the use of microphone arrays or pressure-velocity sensors. The second axis focuses on the excitation part with for instance the use of sound field synthesis techniques. Since acoustic impedance and sound absorption coefficient of materials are classically defined under normal and oblique plane wave excitation, synthesizing an “ideal” plane wave using a loudspeaker array would allow measuring these acoustics quantities using a simple microphone pair. In this article, the effect of the different parameters of a loudspeaker array on acoustic plane waves reproduction on a material’s surface is first numerically studied. Then, numerical and experimental results for the estimation of both impedance and absorption coefficients are reported. These results show that sound field synthesis allows to characterize a material for arbitrary incidence angles over a wide frequency range, thus offering an alternative method to standard techniques and an improvement over existing works.
{"title":"Characterization of acoustic materials at arbitrary incidence angle using sound field synthesis","authors":"S. Dupont, Maryna Sanalatii, M. Melon, O. Robin, A. Berry, J. Le Roux","doi":"10.1051/aacus/2022054","DOIUrl":"https://doi.org/10.1051/aacus/2022054","url":null,"abstract":"Standardized methods for measuring sound absorption such as the impedance tube and reverberation chamber methods are limited to normal or diffuse incidence, respectively. Two research axes have been generally followed in the literature to develop alternative techniques, the first one focusing on the measurement part, that is from the two-microphone technique to the use of microphone arrays or pressure-velocity sensors. The second axis focuses on the excitation part with for instance the use of sound field synthesis techniques. Since acoustic impedance and sound absorption coefficient of materials are classically defined under normal and oblique plane wave excitation, synthesizing an “ideal” plane wave using a loudspeaker array would allow measuring these acoustics quantities using a simple microphone pair. In this article, the effect of the different parameters of a loudspeaker array on acoustic plane waves reproduction on a material’s surface is first numerically studied. Then, numerical and experimental results for the estimation of both impedance and absorption coefficients are reported. These results show that sound field synthesis allows to characterize a material for arbitrary incidence angles over a wide frequency range, thus offering an alternative method to standard techniques and an improvement over existing works.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"27 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83413641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The effective sound speed gradient is used to describe the meteorological conditions during sound measurements at roads and railways. Meteorological parameters were assessed up to a height of 10 m. The sound level differences between a reference point close to the passing vehicles and at distances of 100–500 m from motorways and railway tracks were determined. These differences were found to correlate well with the effective sound speed gradient determined from the measured temperature and wind speed gradients which follow the day/night cycle as a result of the reversing air temperature gradient, incoming solar radiation and wind conditions. The correlation with sound level differences can be approximated by an S-shaped function which is constant for large positive or negative gradients of the effective sound speed. These threshold values are a consequence of the local meteorological and attenuation conditions. The analysis shows that large effective sound speed gradients are mainly a result of the wind conditions whereas gradients without a substantial wind speed contribution are low and a result of the temperature gradient. In the distance range between 150 m and 250 m, the meteorological influences cause a level increase of 3–4 dB(A) for downward refracted sound rays (favourable sound propagation) compared to a situation without meteorological influence (effective sound speed gradient of zero). In the same distance range, meteorological conditions cause a maximum sound level attenuation of 5–10 dB(A) for upward curved sound rays (unfavourable sound propagation).
{"title":"S-shaped dependence of the sound pressure level in outdoor propagation on the effective sound speed gradient","authors":"D. Hohenwarter, E. Mursch-Radlgruber, C. Kirisits","doi":"10.1051/aacus/2022005","DOIUrl":"https://doi.org/10.1051/aacus/2022005","url":null,"abstract":"The effective sound speed gradient is used to describe the meteorological conditions during sound measurements at roads and railways. Meteorological parameters were assessed up to a height of 10 m. The sound level differences between a reference point close to the passing vehicles and at distances of 100–500 m from motorways and railway tracks were determined. These differences were found to correlate well with the effective sound speed gradient determined from the measured temperature and wind speed gradients which follow the day/night cycle as a result of the reversing air temperature gradient, incoming solar radiation and wind conditions. The correlation with sound level differences can be approximated by an S-shaped function which is constant for large positive or negative gradients of the effective sound speed. These threshold values are a consequence of the local meteorological and attenuation conditions. The analysis shows that large effective sound speed gradients are mainly a result of the wind conditions whereas gradients without a substantial wind speed contribution are low and a result of the temperature gradient. In the distance range between 150 m and 250 m, the meteorological influences cause a level increase of 3–4 dB(A) for downward refracted sound rays (favourable sound propagation) compared to a situation without meteorological influence (effective sound speed gradient of zero). In the same distance range, meteorological conditions cause a maximum sound level attenuation of 5–10 dB(A) for upward curved sound rays (unfavourable sound propagation).","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"16 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84795477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
The multilayer structure of surface acoustic wave sensor is an important development direction of surface acoustic wave devices in recent years. In this paper, the IDT/AlN/Mo/diamond structure of surface acoustic wave pressure sensing element is modeled and simulated. The influence of the thickness of AlN and IDT on pressure coefficient frequency and K2 were simulated and analyzed. The performance of surface acoustic wave pressure sensing element is compared when the metal layer is Mo, no metal layer and the metal layer is Pt. Finally, the relationship between frequency variation and pressure of the designed multilayer surface acoustic wave pressure sensing element is obtained. This research provides a good guidance for the design of surface acoustic wave pressure sensor.
{"title":"Design and analysis of SAW pressure sensing element based on IDT/AlN/Mo/diamond multilayered structure","authors":"Xiaoxin Ma, Q. Xiao, Yanping Fan, X. Ji","doi":"10.1051/aacus/2022038","DOIUrl":"https://doi.org/10.1051/aacus/2022038","url":null,"abstract":"The multilayer structure of surface acoustic wave sensor is an important development direction of surface acoustic wave devices in recent years. In this paper, the IDT/AlN/Mo/diamond structure of surface acoustic wave pressure sensing element is modeled and simulated. The influence of the thickness of AlN and IDT on pressure coefficient frequency and K2 were simulated and analyzed. The performance of surface acoustic wave pressure sensing element is compared when the metal layer is Mo, no metal layer and the metal layer is Pt. Finally, the relationship between frequency variation and pressure of the designed multilayer surface acoustic wave pressure sensing element is obtained. This research provides a good guidance for the design of surface acoustic wave pressure sensor.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"40 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73030858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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