Applied Acoustics最新文献

{"title":"A method for extracting an average scattering coefficient for room acoustic modeling","authors":"Dingding Xie ,&nbsp;Wouter Wittebol ,&nbsp;Qi Li ,&nbsp;Maarten Hornikx","doi":"10.1016/j.apacoust.2025.110604","DOIUrl":"10.1016/j.apacoust.2025.110604","url":null,"abstract":"<div><div>This work introduces frequency-dependent Average Scattering Coefficients (ASCs) to quantify the room-averaged degree of scattering per mean free path that results from sound wave interactions with objects, elements, and impedance discontinuities. In this work, the sound field of a room is decomposed into two components: (1) specular reflections from boundary surfaces and (2) non-specular component by the room's interiors and elements. Time-dependent coherence coefficients extracted from impulse responses of furnished rooms and their empty averages are used to derive ASCs, which can be used to facilitate the transition from a specular to a non-specular component in room acoustical modeling. This study extracts ASCs in rooms with varying amounts, distributions, and absorptions of interior elements, and different source and receiver positions based on a wave-based solver. Moreover, ASCs are measured in a real furnished room and utilized to reconstruct the measured sound field with a hybrid model. The specular component is calculated from the empty room case, while the non-specular component is modeled with a stochastic technique. Results from the hybrid models show strong agreement with ground truth regarding early decay time, reverberation time, the degree of scattering, and the level of diffuseness, demonstrating the potential of ASCs for high-frequency room acoustic modeling with reduced computational resources.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110604"},"PeriodicalIF":3.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and evaluation of an acoustic metamaterial for ducted fan noise control","authors":"Wei-Qin Wu,&nbsp;Yong-Bin Zhang,&nbsp;Liang Xu,&nbsp;Liu-Xian Zhao,&nbsp;Ting-Gui Chen","doi":"10.1016/j.apacoust.2025.110612","DOIUrl":"10.1016/j.apacoust.2025.110612","url":null,"abstract":"<div><div>Existing noise control methods for ducted fans usually require modifications to the fan or runner structure, and the installation of silencers may affect ventilation efficiency. In order to address the shortcomings of the above methods, we propose the application of acoustic metamaterials to ducted fan noise control. A Helmholtz-type acoustic metamaterial has been designed to simultaneously control the first four orders of tonal noise, and this metamaterial is characterized by its small size and thin profile, allowing it to be flexibly applied to fan ducts. The acoustic absorption characteristics of this metamaterial, when employed as a duct bypass, have been analyzed using theoretical models and experimental validation. The findings indicate that the acoustic metamaterial exhibit significant acoustic transmission loss at the absorption frequency when employed as a duct bypass. To comprehensively evaluates the effects of acoustic metamaterials on ducted fans, a hybrid simulation approach combining Computational Fluid Dynamics (CFD) with the acoustic Finite Element Method (FEM) is utilized. The numerical simulation results indicate that acoustic metamaterials can effectively attenuate ducted fan noise while maintaining a minimal impact on ventilation efficiency.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110612"},"PeriodicalIF":3.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445765","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}

{"title":"Acoustic characteristics and objective evaluation of acoustic quality in historical Italian theaters","authors":"Ruoran Yan,&nbsp;Lamberto Tronchin","doi":"10.1016/j.apacoust.2024.110483","DOIUrl":"10.1016/j.apacoust.2024.110483","url":null,"abstract":"<div><div>In order to determine an objective range of acoustic parameters for historical Italian theaters and to recommend ideal values for the primary acoustic parameters reverberation time (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>20</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>30</mn></mrow></msub></math></span>), early decay time (<em>EDT</em>), sound strength (<em>G</em>), clarity index (<span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>80</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>50</mn></mrow></msub></math></span>), definition (<span><math><msub><mrow><mi>D</mi></mrow><mrow><mn>50</mn></mrow></msub></math></span>) and interaural cross correlation coefficients (<em>IACC</em>), an acoustic survey of 24 historical Italian theaters spread over 8 regions of Italy was conducted. In the survey, two distinct acoustic measurements were used: 1. Conventional monaural and binaural measurements under unoccupied conditions. 2. Sound field visualization utilizing a 360° camera and an em32/64 Eigenmike®. The geographic distribution features of the 24 theaters, correlations among parameters, performance of each parameter across various frequencies, and dispersion characteristics were analyzed and quantified through computational methods. The acoustic quality of the theaters was ranked according to the statistical results, giving a range of desirable values for each acoustic parameter. It has been discovered that: 1. Correlation analysis indicates that at 1000 Hz, all parameters exhibit the strongest correlations, with a notably strong negative correlation between reverberation time and both clarity index and definition, and a strong positive correlation between clarity index and definition. These results suggest that data at 1000 Hz may be most suitable for machine learning predictions of parameters affected by measurement distance. 2. Boxplot analysis indicates that <em>G</em> is the only parameter without outliers, with variations in other parameters attributed to differences in geographical location, temperature, humidity, theater size, and interior decoration, highlighting the need to consider performance-specific acoustic requirements in evaluations. 3. Objective assessments reveal that most theaters perform best in clarity index values, with Italian historical theaters exhibiting significantly higher <em>G</em>-values, possibly due to factors such as reflective surfaces, stage structure, and architectural design features. 4. Theaters such as Teatro Amintore Galli (Rimini), Teatro dell'Opera (Rome), and Teatro Minimo (Atri) demonstrated notable acoustic performance based on the evaluated parameters.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110483"},"PeriodicalIF":3.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A method of temperature compensation for the ultrasound resonance wind speed and direction sensor in resonance-state","authors":"Xiangbao Zeng ,&nbsp;YuPeng Yuan ,&nbsp;Songlin Liao ,&nbsp;Lu Wang ,&nbsp;Jianan Li ,&nbsp;Qihong Ning ,&nbsp;Hua Yu","doi":"10.1016/j.apacoust.2025.110598","DOIUrl":"10.1016/j.apacoust.2025.110598","url":null,"abstract":"<div><div>Wind power generation, aerospace, meteorology and other key industries have an urgent need for high-precision and high-reliability detection of wind speed and direction. Compared with the traditional mechanical, ultrasonic convective, and ultrasonic reflective wind speed and direction sensors, the ultrasonic resonant wind speed and direction sensing solution in this paper has significant advantages of small size, high accuracy, and no mechanical abrasion. In order to solve the problem of accuracy shift of ultrasonic resonance wind speed and direction sensor under complicated operating conditions, this paper establishes the relationship between the working environment temperature and the resonance frequency point, to realize the temperature compensation of the sensor under different conditions. The wind tunnel test of the sensors under different temperature conditions has been carried out, and the test results show that the wind speed measurement accuracy of the ultrasonic resonance wind speed and direction sensor proposed in this paper is significantly improved after the temperature compensation of the resonance state. After the compensation, the accuracy of wind speed can reach ±0.3 m/s in the wind speed range of less than 15 m/s, and ±2.3 % in the wind speed range of 15 m/s ∼ 50 m/s, improving the accuracy more than 40 % compared with the traditional ultrasonic convection/reflection type. In conclusion, it provides support for more effective wind speed and direction measurements for key areas such as improving the power generation efficiency of wind farm turbines and improving the accuracy of elemental measurements in the meteorological field.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110598"},"PeriodicalIF":3.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445721","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}

{"title":"A novel approach for bird sound classification with cross correlation by denoising with complementary ensemble empirical mode decomposition using B-spline and LSTM features","authors":"Mehmet Bilal Er,&nbsp;Umut Kuran,&nbsp;Nagehan İlhan","doi":"10.1016/j.apacoust.2025.110601","DOIUrl":"10.1016/j.apacoust.2025.110601","url":null,"abstract":"<div><div>This research covers the application of modern signal processing and machine learning techniques for the purpose of denoising and accurately classifying bird sounds. In the study, the signal is separated into smaller components by using the CEEMD (Complete Ensemble Empirical Mode Decomposition) method to clean the background noise of bird sounds. Then, B-Spline functions and LSTM (Long Short-Term Memory) network are used for feature extraction on these cleaned signals. These two methods are effective in capturing important trends and hidden information in the sound signals over time, and a richer feature vector is created. The most important stage of the research is the application of cross-correlation to this feature vector. Cross-correlation provides a powerful analysis tool in terms of timing and pattern detection by analyzing the time delays and similarities between two signals. This process played a major role in determining the similarities between sound signals and increased the classification performance. After feature extraction and cross-correlation, classification is performed using different machine learning algorithms. In general, when cross-correlation is applied, the performance of all algorithms is significantly increased and especially with the C-SVM algorithm, 98.32% accuracy and 98.62% F1 score are obtained. These results show that cross-correlation is a powerful tool in the classification of sound signals and high accuracy rates are achieved when used together with methods such as CEEMD, B-Spline and LSTM. The results of this study show that modern signal processing techniques are effective in the analysis of complex sound signals such as bird sounds and cross-correlation is a critical step in improving the classification performance.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110601"},"PeriodicalIF":3.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445876","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}

{"title":"Design of sawtooth-shaped acoustic metasurface for reflective wave manipulation","authors":"Mu He ,&nbsp;Zhe Zhu ,&nbsp;Wei-Zhi Luo ,&nbsp;Bo Song ,&nbsp;Liang Xia","doi":"10.1016/j.apacoust.2025.110614","DOIUrl":"10.1016/j.apacoust.2025.110614","url":null,"abstract":"<div><div>Currently, the goal of research on acoustic metasurfaces is mainly focused on achieving ultimate sound wave control, which often requires complex structural design. However, complex structures are often difficult to fabricate and apply on a large scale. To this end, our study investigates a sawtooth-shaped metasurface with a simple configuration, easy fabrication and good wave control capability. First, we used the “apparent wavefront theory” and the “lattice diffraction theory” to predict the main reflected angles induced by sawtooth metasurfaces with varying tooth angles. Then, numerical simulations were performed to validate the theories used and to analyze the conditions of their applicability. Finally, several configurations of sawtooth metasurfaces were designed to realize different functions such as large-angle deflection, acoustic focusing and uniform diffusion, which can also be verified experimentally. In general terms, the sawtooth-shaped metasurface has broad prospects in sound wave manipulation.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110614"},"PeriodicalIF":3.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445722","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}

{"title":"Experimental and theoretical investigating on measurement of dynamic response characteristics of the semi-infinite pressure tube with non-uniform temperature","authors":"Longchao Xu ,&nbsp;Yunpeng Liu ,&nbsp;Ronghui Cheng ,&nbsp;Yingwen Yan","doi":"10.1016/j.apacoust.2025.110589","DOIUrl":"10.1016/j.apacoust.2025.110589","url":null,"abstract":"<div><div>In combustion instability experiments, oscillatory pressure is commonly sampled using a semi-infinite pressure tube, but the non-uniform temperature distribution adds complexity to the correction of oscillatory pressure. This paper innovatively investigates the impact of non-uniform temperature distribution on the dynamic response characteristics of semi-infinite pressure tubes using a one-dimensional discrete method for sound propagation, obtaining the distribution of sound pressure gain and phase difference in the pressure tube. The results indicate that the end of the semi-infinite pressure tube can be approximated as a non-reflective boundary; however, the presence of sensor mounts on the sidewalls of the pressure tube creates small cavity structures that reflect sound waves, leading to non-monotonic characteristics in the dynamic response of the pressure tube. An increase in pressure tube root temperature reduces the traveling wave specific acoustic impedance, amplifying the pressure tube gain. At a pressure tube root temperature of 500 °C, the temperature non-uniformity effect overall amplifies the gain by about 1.2 times. By establishing a one-dimensional sound wave propagation theory analysis, combined with acoustic simulation and experimental verification, this paper reveals the mechanism of action of non-uniform temperature fields on the dynamic response within pressure tube, providing theoretical guidance for correcting oscillatory pressure measurements in combustion instability of gas turbines and aero-engines.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110589"},"PeriodicalIF":3.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427805","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}

{"title":"Nondestructive evaluation of spheroidization grades based on entropy characteristic parameters method","authors":"Jinlong Li ,&nbsp;Zenghua Liu ,&nbsp;Zongjian Zhang ,&nbsp;Yang Zheng ,&nbsp;Cunfu He","doi":"10.1016/j.apacoust.2025.110599","DOIUrl":"10.1016/j.apacoust.2025.110599","url":null,"abstract":"<div><div>Due to its excellent mechanical properties, 15CrMo steel is widely used in critical components exposed for high-temperature and high-pressure conditions. Long term high-temperature will increase the spheroidization possibility and even cause serious safety accidents. However, characterization of the spheroidization grades is a very difficult problem. To quantitatively evaluate the spheroidization grades of 15CrMo steel, destructive testing methods are used to determine spheroidization grades. This study uses the ultrasonic backscattering method to detect the spheroidization grades. The ultrasonic testing platform collects the backscattering signals, and the typical characteristic parameters and entropy characteristic parameters of the backscattering signals are extracted. New entropy characteristic parameters, including the information entropy, conditional entropy, sample entropy, fuzzy entropy, permutation entropy, approximate entropy, power spectral entropy, and singular spectrum entropy, are introduced to evaluate the spheroidization grades of 15CrMo steel. It is found that the proposed entropy characteristic parameters can reflect the changes in the microstructure under different spheroidization grades. Therefore, the entropy characteristic parameters of ultrasonic backscattering signals are advantageous for evaluating the spheroidization grades of 15CrMo steel.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110599"},"PeriodicalIF":3.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427804","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}

{"title":"A novel time-of-flight difference determination method for ultrasonic thickness measurement with ultrasonic echo onset point detection","authors":"Wangyu Liu ,&nbsp;Dongxun Li ,&nbsp;Weigui Xie","doi":"10.1016/j.apacoust.2025.110605","DOIUrl":"10.1016/j.apacoust.2025.110605","url":null,"abstract":"<div><div>Determining the time-of-flight difference (TOFD) between adjacent echoes is essential for accurate ultrasonic thickness measurement. However, due to energy attenuation, time shift and frequency dispersion during the propagation process, the actual received ultrasonic signal will always have waveform changes and noise interference, and it is challenging to ensure satisfactory accuracy using traditional methods. Herein, A TOFD determination method based on ultrasonic echo onset point (UEOP) detection was proposed. The method combines the optimal main energy spectrum (ODES) and Akaike information criterion (AIC) to detect the UEOP of ultrasonic echo, and then determines the TOFD based on the UEOP of adjacent echoes. Numerical experiments were carried out to evaluate the detection performance of the proposed method under waveform change and different noise levels. Experimental validation of ultrasonic thickness measurement on aluminum alloy samples shows that the proposed method can obtain accurate thickness measurement results.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110605"},"PeriodicalIF":3.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436431","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}

{"title":"Block-wise superposition-based frequency-domain synthetic aperture focusing imaging of leaky Rayleigh waves","authors":"Hongwei Hu ,&nbsp;Decao Yang ,&nbsp;Duo Lyu ,&nbsp;Xiaofei Luo ,&nbsp;Xiaomin Chen","doi":"10.1016/j.apacoust.2025.110597","DOIUrl":"10.1016/j.apacoust.2025.110597","url":null,"abstract":"<div><div>Leaky Rayleigh waves can be used to detect surface or sub-surface defects. The main advantage of this type of non-contact detection method is that it is easy to realize automatic inspections. However, due to the need for waveform conversion and propagation attenuation, the echo amplitudes of leaky Rayleigh waves are small, making them highly susceptible to noise, which is not conducive to defect detection and large-area imaging. A method that combines principal component analysis (PCA) with wavelet-based hidden Markov model (WHMM) algorithms is presented to denoise leaky Rayleigh waves. Subsequently, multiple sets of denoised B-scan data are then subjected to distance amplitude curve (DAC) attenuation compensation and frequency-domain synthetic aperture focusing technique (F-SAFT) for imaging. Finally, to achieve large-area imaging, F-SAFT processed data are superimposed and stitched together using a block-wise superposition method. Compared with B-scan data stitching imaging, the proposed method has a detection time of only 1/24 of that of B-scanning while reducing the average defect size error by 21.5 %, thus effectively improving the imaging efficiency and resolution for surface defect detection.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"233 ","pages":"Article 110597"},"PeriodicalIF":3.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427959","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}