Applied Acoustics最新文献_第6页

A Bayesian subspace equivalent source method based on proper orthogonal decomposition for jet noise identification 基于适当正交分解的贝叶斯子空间等效源方法用于射流噪声识别

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-10 DOI: 10.1016/j.apacoust.2025.111188

Liangshuo Yuan , Daofang Feng , Youtai Shi , Qixin Guo , Junjian Hou , Liang Yu , Yudong Zhong

Jet noise source identification represents an important research direction in the field of aeroacoustics and has significant importance for aviation engine noise reduction and environmental protection. Jet noise belongs to typical distributed coherent sources, and strong coherence generated by large-scale turbulent structures poses major challenges to traditional acoustic source identification methods. To address this problem, this paper proposes a Bayesian subspace equivalent source method based on proper orthogonal decomposition (POD). The proposed method first extracts the primary coherent structures of acoustic fields through proper orthogonal decomposition, effectively suppressing background noise interference. The method then establishes a Bayesian regularization framework that utilizes marginal likelihood functions to achieve automatic optimization of regularization parameters, effectively avoiding singularities in inverse problems. Algorithm performance was systematically validated through three approaches: line source simulations, large eddy simulation data analysis of Mach 0.9 jets, and free jet wind tunnel experiments. The validation successfully separated and localized the spatial distribution of jet noise sources under different Strouhal number conditions. Results demonstrate that the proposed method has good reconstruction accuracy and directivity characteristics within the large-scale turbulent frequency range. Compared to traditional equivalent source methods, the proposed method exhibits significant advantages in acoustic source distribution characteristic estimation. The advantages are primarily attributed to the synergistic effect of intrinsic coherence between source decomposition techniques and equivalent sources.

射流噪声源识别是航空声学领域的一个重要研究方向，对航空发动机降噪和环境保护具有重要意义。射流噪声属于典型的分布式相干源，大尺度湍流结构产生的强相干性对传统声源识别方法提出了重大挑战。针对这一问题，提出了一种基于适当正交分解（POD）的贝叶斯子空间等效源方法。该方法首先通过适当的正交分解提取声场的主相干结构，有效抑制背景噪声干扰。该方法建立了贝叶斯正则化框架，利用边际似然函数实现正则化参数的自动优化，有效地避免了反问题中的奇异性。通过线源仿真、0.9马赫射流大涡模拟数据分析和自由射流风洞实验三种方法系统验证了算法的性能。验证成功地分离和定位了不同斯特罗哈尔数条件下射流噪声源的空间分布。结果表明，该方法在大范围湍流频率范围内具有良好的重构精度和指向性。与传统等效源方法相比，该方法在声源分布特征估计方面具有显著优势。这些优势主要归功于源分解技术和等效源之间的内在相干性的协同效应。

{"title":"A Bayesian subspace equivalent source method based on proper orthogonal decomposition for jet noise identification","authors":"Liangshuo Yuan , Daofang Feng , Youtai Shi , Qixin Guo , Junjian Hou , Liang Yu , Yudong Zhong","doi":"10.1016/j.apacoust.2025.111188","DOIUrl":"10.1016/j.apacoust.2025.111188","url":null,"abstract":"<div><div>Jet noise source identification represents an important research direction in the field of aeroacoustics and has significant importance for aviation engine noise reduction and environmental protection. Jet noise belongs to typical distributed coherent sources, and strong coherence generated by large-scale turbulent structures poses major challenges to traditional acoustic source identification methods. To address this problem, this paper proposes a Bayesian subspace equivalent source method based on proper orthogonal decomposition (POD). The proposed method first extracts the primary coherent structures of acoustic fields through proper orthogonal decomposition, effectively suppressing background noise interference. The method then establishes a Bayesian regularization framework that utilizes marginal likelihood functions to achieve automatic optimization of regularization parameters, effectively avoiding singularities in inverse problems. Algorithm performance was systematically validated through three approaches: line source simulations, large eddy simulation data analysis of Mach 0.9 jets, and free jet wind tunnel experiments. The validation successfully separated and localized the spatial distribution of jet noise sources under different Strouhal number conditions. Results demonstrate that the proposed method has good reconstruction accuracy and directivity characteristics within the large-scale turbulent frequency range. Compared to traditional equivalent source methods, the proposed method exhibits significant advantages in acoustic source distribution characteristic estimation. The advantages are primarily attributed to the synergistic effect of intrinsic coherence between source decomposition techniques and equivalent sources.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"245 ","pages":"Article 111188"},"PeriodicalIF":3.4,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748730","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}

引用次数: 0

A hybrid meta-structure with topology-optimized composite porous material and Helmholtz resonator for low-frequency and broadband sound absorption 具有拓扑优化的复合多孔材料和用于低频和宽带吸声的亥姆霍兹谐振腔的混合元结构

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-08 DOI: 10.1016/j.apacoust.2025.111189

Feifei Feng, Chuan He, Lei Diao, Shihao Tang, Meng Tao

A hybrid meta-structure composed of composite porous material modulation crowns and Helmholtz resonators with embedded porous material is designed for low-frequency, broadband, and highly efficient sound absorption. The sound absorption coefficients of the hybrid meta-structure are calculated by combining the equivalent medium theory and the double porosity theory, and their accuracy is validated through an experimental method and a finite element method. The acoustic performance of the hybrid meta-structure is analyzed, and it is shown that, similar to the traditional Helmholtz resonator, the hybrid meta-structure can trigger the resonance sound absorption mechanism. In comparison with the Helmholtz resonator with embedded porous material and the traditional Helmholtz resonator, the hybrid meta-structure has a lower peak frequency and a broader absorption band. Driven by the embedded porous material and composite porous material modulation crown, the cavity dominates the sound energy dissipation near the resonance frequency, and the hybrid meta-structure retains a certain sound energy dissipation capability away from the resonance frequency. Finally, a hybrid meta-structure consisting of nine subunits in parallel is designed, and the Helmholtz resonators with embedded porous material and composite porous material modulation crowns are sequentially designed using a structural optimization algorithm and a non-gradient topology optimization algorithm. The optimized hybrid meta-structure with a thickness of 60 mm achieved highly efficient absorption (

α \geq 0.8

) across a frequency band of [289 1230] Hz, which can be widely used for low-frequency noise control at subwavelength scales in various engineering fields.

设计了一种由复合多孔材料调制冠和嵌入多孔材料的亥姆霍兹谐振器组成的混合元结构，用于低频、宽带和高效吸声。结合等效介质理论和双重孔隙理论计算了混合元结构的吸声系数，并通过实验方法和有限元方法验证了其准确性。对混合元结构的声学性能进行了分析，结果表明，混合元结构与传统亥姆霍兹谐振腔相似，能够触发共振吸声机制。与嵌入多孔材料的亥姆霍兹谐振腔和传统亥姆霍兹谐振腔相比，混合元结构具有更低的峰值频率和更宽的吸收带。在嵌入多孔材料和复合多孔材料调制冠的驱动下，腔体主导共振频率附近的声能耗散，混合元结构在远离共振频率处保持一定的声能耗散能力。最后，设计了一个由9个子单元并联组成的混合元结构，采用结构优化算法和非梯度拓扑优化算法，依次设计了嵌入多孔材料和复合多孔材料调制冠的亥姆霍兹谐振器。优化后的混合元结构厚度为60 mm，在[289 1230]Hz频段内实现了高效吸收（α≥0.8），可广泛应用于各种工程领域的亚波长尺度低频噪声控制。

{"title":"A hybrid meta-structure with topology-optimized composite porous material and Helmholtz resonator for low-frequency and broadband sound absorption","authors":"Feifei Feng, Chuan He, Lei Diao, Shihao Tang, Meng Tao","doi":"10.1016/j.apacoust.2025.111189","DOIUrl":"10.1016/j.apacoust.2025.111189","url":null,"abstract":"<div><div>A hybrid <em>meta</em>-structure composed of composite porous material modulation crowns and Helmholtz resonators with embedded porous material is designed for low-frequency, broadband, and highly efficient sound absorption. The sound absorption coefficients of the hybrid <em>meta</em>-structure are calculated by combining the equivalent medium theory and the double porosity theory, and their accuracy is validated through an experimental method and a finite element method. The acoustic performance of the hybrid <em>meta</em>-structure is analyzed, and it is shown that, similar to the traditional Helmholtz resonator, the hybrid <em>meta</em>-structure can trigger the resonance sound absorption mechanism. In comparison with the Helmholtz resonator with embedded porous material and the traditional Helmholtz resonator, the hybrid <em>meta</em>-structure has a lower peak frequency and a broader absorption band. Driven by the embedded porous material and composite porous material modulation crown, the cavity dominates the sound energy dissipation near the resonance frequency, and the hybrid <em>meta</em>-structure retains a certain sound energy dissipation capability away from the resonance frequency. Finally, a hybrid <em>meta</em>-structure consisting of nine subunits in parallel is designed, and the Helmholtz resonators with embedded porous material and composite porous material modulation crowns are sequentially designed using a structural optimization algorithm and a non-gradient topology optimization algorithm. The optimized hybrid <em>meta</em>-structure with a thickness of 60 mm achieved highly efficient absorption (<span><math><mrow><mi>α</mi><mo>≥</mo><mn>0.8</mn></mrow></math></span>) across a frequency band of [289 1230] Hz, which can be widely used for low-frequency noise control at subwavelength scales in various engineering fields.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"245 ","pages":"Article 111189"},"PeriodicalIF":3.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749022","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}

引用次数: 0

Sound propagation over periodically grooved convex surfaces 声音在有周期性凹槽的凸表面上传播

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-08 DOI: 10.1016/j.apacoust.2025.111177

David L. Berry , Shahram Taherzadeh , Keith Attenborough

A numerical Boundary Element Method is used to investigate the propagation of cylindrical sound waves over rigid, grooved, convex surfaces at audio-frequencies. Laboratory measurements with broadband excitation and corresponding predictions reveal peaks in excess attenuation spectra. With short pulse excitation, measurements and predictions show delayed signals or “tails” following the main pulse arrivals. The spectral content of these tails corresponds to the peaks on the excess attenuation spectra and can be attributed to organ pipe (or quarter wavelength) resonance in the grooves. Predictions of the two-dimensional distribution of sound at the frequencies of these peaks show that the pressure field is restricted to a thin layer above the curved grooved surface, indicative of a surface wave which is eliminated by a very high finite impedance.

采用数值边界元法研究了圆柱声波在刚性、沟槽、凸表面上的传播。宽带激励的实验室测量和相应的预测揭示了过量衰减光谱的峰值。在短脉冲激励下，测量和预测显示主脉冲到达后的延迟信号或“尾巴”。这些尾部的光谱含量与过量衰减光谱上的峰值相对应，可以归因于沟槽中的风琴管（或四分之一波长）共振。对这些峰值频率的二维声分布的预测表明，压力场被限制在弯曲沟槽表面上方的薄层，表明表面波被非常高的有限阻抗所消除。

引用次数: 0

Aeroacoustic impact of heat exchanger installation in an industrial engine cooling module 工业发动机冷却模块中热交换器安装的气动声学影响

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-07 DOI: 10.1016/j.apacoust.2025.111175

Francesco Bellelli , Renzo Arina , Stéphane Moreau , Francesco Avallone

Engine cooling fan noise becomes even more difficult to predict when considering the presence of the heat exchanger upstream. This paper investigates the impact of different heat exchanger installations on the noise sources of an industrial engine cooling fan using high-fidelity lattice-Boltzmann simulations. The heat exchanger is simulated using an equivalent porous medium upstream of the fan. Four configurations are analyzed at free discharge: full cooling module (i) without and (ii) with a gap between the heat exchanger and its casing, (iii) Fan+Frame, and (iv) Fan. For the sake of comparison, configurations (iii) and (iv) are simulated by imposing a pressure difference that matches the one across the heat exchanger, to ensure that the same operating point is maintained. Results show negligible differences in the overall aerodynamic performance since the same average pressure rise is achieved. The presence of the porous medium affects the spatial distribution of the pressure field upstream of the fan, thus causing a higher tonal content compared to the configurations (iii) and (iv). Further subharmonic humps are caused by the interaction of the blades with vortex structures generated by flow separation at the tip and the casing’s support structures. The presence of a geometry transition from square to round in the casing causes inflow distortions, increasing low-frequency broadband noise.

当考虑到上游热交换器的存在时，发动机冷却风扇的噪音变得更加难以预测。本文采用高保真栅格-玻尔兹曼模拟研究了不同换热器安装方式对工业发动机冷却风扇噪声源的影响。热交换器采用风扇上游的等效多孔介质进行模拟。在自由排放的情况下，分析了四种配置：全冷却模块(i)无热交换器与外壳之间的间隙和（ii）有热交换器与外壳之间的间隙，（iii）风扇+框架，（iv）风扇。为了进行比较，通过施加与热交换器上的压差相匹配的压差来模拟配置（iii）和（iv），以确保保持相同的工作点。结果表明，由于实现了相同的平均压力上升，整体气动性能的差异可以忽略不计。多孔介质的存在影响了风机上游压力场的空间分布，从而导致比配置（iii）和（iv）更高的音调含量。进一步的次谐波峰是由叶片与叶尖处流动分离和机匣支撑结构产生的涡结构相互作用引起的。套管中从方形到圆形的几何转变会导致流入扭曲，增加低频宽带噪声。

{"title":"Aeroacoustic impact of heat exchanger installation in an industrial engine cooling module","authors":"Francesco Bellelli , Renzo Arina , Stéphane Moreau , Francesco Avallone","doi":"10.1016/j.apacoust.2025.111175","DOIUrl":"10.1016/j.apacoust.2025.111175","url":null,"abstract":"<div><div>Engine cooling fan noise becomes even more difficult to predict when considering the presence of the heat exchanger upstream. This paper investigates the impact of different heat exchanger installations on the noise sources of an industrial engine cooling fan using high-fidelity lattice-Boltzmann simulations. The heat exchanger is simulated using an equivalent porous medium upstream of the fan. Four configurations are analyzed at free discharge: full cooling module (i) without and (ii) with a gap between the heat exchanger and its casing, (iii) Fan+Frame, and (iv) Fan. For the sake of comparison, configurations (iii) and (iv) are simulated by imposing a pressure difference that matches the one across the heat exchanger, to ensure that the same operating point is maintained. Results show negligible differences in the overall aerodynamic performance since the same average pressure rise is achieved. The presence of the porous medium affects the spatial distribution of the pressure field upstream of the fan, thus causing a higher tonal content compared to the configurations (iii) and (iv). Further subharmonic humps are caused by the interaction of the blades with vortex structures generated by flow separation at the tip and the casing’s support structures. The presence of a geometry transition from square to round in the casing causes inflow distortions, increasing low-frequency broadband noise.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"245 ","pages":"111175"},"PeriodicalIF":3.4,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694777","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}

引用次数: 0

Acoustic wave propagation in multiscale permeable sorptive metamaterials 声波在多尺度可渗透吸附超材料中的传播

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-07 DOI: 10.1016/j.apacoust.2025.111178

C.C. Parra , R. Venegas , J. Rebolledo , J.P. Arenas , F. Orellana

This paper introduces a general theoretical framework for the modeling of long-wavelength acoustic wave propagation in multiscale rigid-frame permeable sorptive metamaterials. This class of materials results from the combination of multiscale sorptive porous materials, which possess characteristic sizes ranging from nanometres up to millimetres, a mesopore fluid network, and local acoustic resonators. The two-scale asymptotic homogenisation method is used to establish the macroscopic equations that describe sound propagation through the investigated class of materials. The upscaling process unveils the key role of internal mass sources, activated by pressure, on the macroscopic mass balance, while the macroscopic fluid flow constitutive law remains classical. Phenomena such as inner acoustic resonances, multiple types of diffusion, visco-thermal dissipation across scales, and sorption at the nanoscale, are shown to determine the atypical effective compressibility of the fluid equivalent to the metamaterial. The dynamic permeability behaves classically, however, and is determined by the most permeable local constituent. We develop an analytical model for a material with a specific microstructure and successfully validate it against numerical pore-scale simulations and experimental data from a prototype sample whose key building-block elements are granular activated carbon and 3D-printed acoustic resonators. This work paves the way for the bottom-up design of materials that can exploit multiphysics and multiscale phenomena for acoustic wave control applications.

本文介绍了长波长声波在多尺度刚构渗透吸附超材料中传播的一般理论框架。这类材料是由多尺度吸附多孔材料组合而成的，多孔材料具有从纳米到毫米的特征尺寸、介孔流体网络和局部声学谐振器。采用双尺度渐近均匀化方法建立了描述声音在所研究材料中传播的宏观方程。升级过程揭示了由压力激活的内部质量源对宏观质量平衡的关键作用，而宏观流体流动本构律仍然是经典的。研究表明，内部声学共振、多种类型的扩散、跨尺度的粘热耗散和纳米尺度的吸附等现象决定了与超材料等效的流体的非典型有效可压缩性。然而，动态渗透率的表现是经典的，并由最具渗透性的局部成分决定。我们为具有特定微观结构的材料开发了一个分析模型，并成功地通过数值孔隙尺度模拟和来自原型样品的实验数据验证了它，原型样品的关键构建块元素是颗粒活性炭和3d打印声学谐振器。这项工作为自下而上的材料设计铺平了道路，这些材料可以利用多物理场和多尺度现象进行声波控制应用。

{"title":"Acoustic wave propagation in multiscale permeable sorptive metamaterials","authors":"C.C. Parra , R. Venegas , J. Rebolledo , J.P. Arenas , F. Orellana","doi":"10.1016/j.apacoust.2025.111178","DOIUrl":"10.1016/j.apacoust.2025.111178","url":null,"abstract":"<div><div>This paper introduces a general theoretical framework for the modeling of long-wavelength acoustic wave propagation in multiscale rigid-frame permeable sorptive metamaterials. This class of materials results from the combination of multiscale sorptive porous materials, which possess characteristic sizes ranging from nanometres up to millimetres, a mesopore fluid network, and local acoustic resonators. The two-scale asymptotic homogenisation method is used to establish the macroscopic equations that describe sound propagation through the investigated class of materials. The upscaling process unveils the key role of internal mass sources, activated by pressure, on the macroscopic mass balance, while the macroscopic fluid flow constitutive law remains classical. Phenomena such as inner acoustic resonances, multiple types of diffusion, visco-thermal dissipation across scales, and sorption at the nanoscale, are shown to determine the atypical effective compressibility of the fluid equivalent to the metamaterial. The dynamic permeability behaves classically, however, and is determined by the most permeable local constituent. We develop an analytical model for a material with a specific microstructure and successfully validate it against numerical pore-scale simulations and experimental data from a prototype sample whose key building-block elements are granular activated carbon and 3D-printed acoustic resonators. This work paves the way for the bottom-up design of materials that can exploit multiphysics and multiscale phenomena for acoustic wave control applications.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"245 ","pages":"111178"},"PeriodicalIF":3.4,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694778","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}

引用次数: 0

Prediction of subjective annoyance penalty of impulsive noise based on objective measurements 基于客观测量的脉冲噪声主观烦恼惩罚预测

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-06 DOI: 10.1016/j.apacoust.2025.111186

Valtteri Hongisto, Ville Rajala , Pekka Saarinen

Many regulations and standards penalize noise with an impulsive character by adding a constant correction to the measured equivalent A-weighted sound level, L_Aeq. This is expected to correspond better with perceived annoyance. Annoyance with impulsive noise may not correlate with such a simple procedure. The ISO/PAS 1996-3 describes a method for the measurement of onset rate and level difference of impulses and offers an objective procedure to calculate the penalty. Purpose of our study is to compare the results of this and four other procedures with experimental psychoacoustics data. Based on these comparisons, a procedure that uses the difference between the 1 and 99 percentile levels is recommended for assessing outdoor impulsive sounds in the range 45–65 dB L_Aeq because of its simplicity.

许多法规和标准通过对测量的等效a加权声级LAeq进行恒定校正来惩罚具有脉冲特征的噪声。预计这与感知到的烦恼会更好地对应。对脉冲噪声的烦恼可能与这样一个简单的过程无关。ISO/PAS 1996-3描述了一种测量脉冲启动率和电平差的方法，并提供了一个计算惩罚的客观程序。本研究的目的是将此方法和其他四种方法的结果与实验心理声学数据进行比较。基于这些比较，建议使用1和99百分位水平之间的差异来评估45-65 dB LAeq范围内的室外脉冲声音，因为它很简单。

引用次数: 0

Apertured electrical coils for sound radiation reduction 减少声辐射的多孔线圈

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-05 DOI: 10.1016/j.apacoust.2025.111179

Carlos García A., Amine Benamar, Vincent Lanfranchi, Nicolas Dauchez

Industrial coils, such as air-core dry-type reactors, are well known for emitting high-level low-frequency electromagnetic-induced noise. This type of noise generally results from Lorentz forces exciting the coil. In this study, we investigate the effects of introducing apertures into air-core dry-type reactors on the acoustic radiation and associated dynamic behaviors. A simple analytical model of a coil section is first presented to illustrate how porosity, i.e. the aperture size, changes the radiated acoustic pressure. This model shows the variations in pressure inside and outside the coil, as well as the overall dynamic behavior of the most radiating mode in thin shells, i.e. the “ring mode". The transition from solid to apertured structures has interesting dynamical consequences: coupled structural modes detach and change the overall dynamics and acoustics, in ways that are not captured by the simplified model. We investigate these effects through a three-step simulation—electromagnetic, mechanical, and acoustic—which reveals that apertured coils exhibit notably lower acoustic radiation efficiency compared to solid structures, with a reduction of approximately 15 dB at 100 Hz. Thus, our findings offer useful considerations for the design and optimization of apertured coils to decrease acoustic noise generation.

工业线圈，如空芯干式电抗器，以发射高水平低频电磁诱发噪声而闻名。这种类型的噪声通常是由激励线圈的洛伦兹力引起的。在这项研究中，我们研究了在空心干式电抗器中引入孔对声辐射和相关动力学行为的影响。首先提出了一个简单的线圈截面解析模型来说明孔隙度（即孔径大小）如何改变辐射声压。该模型显示了线圈内外压力的变化，以及薄壳中辐射最大的模式，即“环模式”的整体动态行为。从固体结构到多孔结构的转变具有有趣的动力学结果：耦合结构模式分离并以简化模型未捕获的方式改变整体动力学和声学。我们通过电磁、机械和声学三步模拟来研究这些影响，结果表明，与固体结构相比，孔径线圈的声辐射效率明显较低，在100 Hz时降低了约15 dB。因此，我们的研究结果为孔径线圈的设计和优化提供了有益的考虑，以减少噪声的产生。

{"title":"Apertured electrical coils for sound radiation reduction","authors":"Carlos García A., Amine Benamar, Vincent Lanfranchi, Nicolas Dauchez","doi":"10.1016/j.apacoust.2025.111179","DOIUrl":"10.1016/j.apacoust.2025.111179","url":null,"abstract":"<div><div>Industrial coils, such as air-core dry-type reactors, are well known for emitting high-level low-frequency electromagnetic-induced noise. This type of noise generally results from Lorentz forces exciting the coil. In this study, we investigate the effects of introducing apertures into air-core dry-type reactors on the acoustic radiation and associated dynamic behaviors. A simple analytical model of a coil section is first presented to illustrate how porosity, i.e. the aperture size, changes the radiated acoustic pressure. This model shows the variations in pressure inside and outside the coil, as well as the overall dynamic behavior of the most radiating mode in thin shells, i.e. the “ring mode\". The transition from solid to apertured structures has interesting dynamical consequences: coupled structural modes detach and change the overall dynamics and acoustics, in ways that are not captured by the simplified model. We investigate these effects through a three-step simulation—electromagnetic, mechanical, and acoustic—which reveals that apertured coils exhibit notably lower acoustic radiation efficiency compared to solid structures, with a reduction of approximately 15 dB at 100 Hz. Thus, our findings offer useful considerations for the design and optimization of apertured coils to decrease acoustic noise generation.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"245 ","pages":"Article 111179"},"PeriodicalIF":3.4,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694780","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}

引用次数: 0

Vertically spaced ring-like elastic metamaterials for broadband tunability of low-frequency flexural waves 用于低频弯曲波宽带可调性的垂直间隔环形弹性超材料

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-12-01 DOI: 10.1016/j.apacoust.2025.111176

Duy Binh Pham, Shyh-Chour Huang

Achieving continuous and stable tunability of local resonators without requiring ongoing external stimuli, while maintaining a broad low-frequency bandgap, remains a significant challenge in elastic metamaterials. This study introduces a novel tunable metamaterial for flexural wave isolation, consisting of a compact elastic ring-like frame integrated with a central mass block formed by bolt–nut–gasket assemblies. Tunability is attained by adjusting the vertical separation between two stacked elastic layers through the rotational angle of threaded nuts, thereby modulating the system’s flexural stiffness. This approach enables continuous, reversible, and passive control of flexural wave propagation. The tuning mechanism is systematically investigated through theoretical modeling, finite element simulations, and experimental validation, encompassing dispersion analysis and frequency response studies of both infinite and finite structures. Results confirm the effectiveness of the proposed design in low-frequency vibration attenuation. Parametric studies further elucidate the role of geometric features on bandgap tunability. Potential applications, including vibration isolation, flexural wave barriers, and external vibration absorption for tubular structures, are demonstrated, and a comparative evaluation highlights the advantages of the proposed design relative to state-of-the-art tunable metamaterials.

在不需要持续的外部刺激的情况下实现局部谐振器的连续和稳定的可调性，同时保持宽的低频带隙，仍然是弹性超材料的重大挑战。本研究介绍了一种新型的可调弯曲波隔离材料，它由一个紧凑的弹性环形框架和一个由螺栓-螺母-垫片组合而成的中心质量块组成。可调性是通过螺纹螺母的旋转角度来调节两个堆叠弹性层之间的垂直距离，从而调节系统的抗弯刚度。这种方法可以实现对弯曲波传播的连续、可逆和被动控制。通过理论建模、有限元模拟和实验验证，系统地研究了调谐机制，包括无限和有限结构的色散分析和频率响应研究。结果证实了该设计在低频振动抑制方面的有效性。参数化研究进一步阐明了几何特征对带隙可调性的影响。潜在的应用，包括隔振、弯曲波屏障和管状结构的外部振动吸收，都被展示出来，对比评估突出了相对于最先进的可调超材料，所提出的设计的优势。

{"title":"Vertically spaced ring-like elastic metamaterials for broadband tunability of low-frequency flexural waves","authors":"Duy Binh Pham, Shyh-Chour Huang","doi":"10.1016/j.apacoust.2025.111176","DOIUrl":"10.1016/j.apacoust.2025.111176","url":null,"abstract":"<div><div>Achieving continuous and stable tunability of local resonators without requiring ongoing external stimuli, while maintaining a broad low-frequency bandgap, remains a significant challenge in elastic metamaterials. This study introduces a novel tunable metamaterial for flexural wave isolation, consisting of a compact elastic ring-like frame integrated with a central mass block formed by bolt–nut–gasket assemblies. Tunability is attained by adjusting the vertical separation between two stacked elastic layers through the rotational angle of threaded nuts, thereby modulating the system’s flexural stiffness. This approach enables continuous, reversible, and passive control of flexural wave propagation. The tuning mechanism is systematically investigated through theoretical modeling, finite element simulations, and experimental validation, encompassing dispersion analysis and frequency response studies of both infinite and finite structures. Results confirm the effectiveness of the proposed design in low-frequency vibration attenuation. Parametric studies further elucidate the role of geometric features on bandgap tunability. Potential applications, including vibration isolation, flexural wave barriers, and external vibration absorption for tubular structures, are demonstrated, and a comparative evaluation highlights the advantages of the proposed design relative to state-of-the-art tunable metamaterials.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"245 ","pages":"Article 111176"},"PeriodicalIF":3.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694268","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}

引用次数: 0

Analog emulator designs for the auditory neurons and their performance comparison with the dynamic time warping algorithm 听觉神经元模拟模拟器的设计及其与动态时间规整算法的性能比较

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-11-28 DOI: 10.1016/j.apacoust.2025.111173

Nimet Korkmaz, Mustafa Molu

In auditory system, after the frequencies of sound signals are modulated by the basilar membrane, these sounds of different frequencies are processed by different auditory neurons. Design of the broadband electronic circuits is a critical issue to emulate the auditory neurons, because these emulator circuit processes the sound signal of various frequency without require any update. In this study, it is aimed to compare the response performance of the auditory neuron emulator circuits that are built by several analog devices. In this context, an auditory neuron model, which is defined by adapting the vibrations in a piezoelectric ceramic to the FitzHugh–Nagumo neuron model, is successfully implemented with voltage operational amplifier, operational transconductance amplifiers, current feedback operational amplifiers and field programmable analog arrays. After the notes of a musical composition are coded in a microcontroller, its electrical signal output is applied to the auditory neuron emulator circuits as an external excitation signal. The peaks of the excitation signal applying to the emulator circuits and the firing times of the dynamic responses measuring from the outputs of these analog circuits are recorded simultaneously. Then, time differences between stimulus peaks and neuronal firing responses are determined with the “Dynamic Time Warping” algorithm and the input/output synchronization performances of these analog emulators are compared according to the result of this quantitative measurement.

在听觉系统中，声音信号的频率经过基底膜的调制后，这些不同频率的声音被不同的听觉神经元处理。宽带电子电路的设计是模拟听觉神经元的关键问题，因为这些仿真电路可以处理不同频率的声音信号而不需要任何更新。在本研究中，旨在比较由几种模拟设备构建的听觉神经元仿真电路的响应性能。在此背景下，通过将压电陶瓷中的振动适应FitzHugh-Nagumo神经元模型来定义听觉神经元模型，并成功地实现了电压运算放大器，运算跨导放大器，电流反馈运算放大器和现场可编程模拟阵列。乐曲的音符在微控制器中编码后，其电信号输出作为外部激励信号被应用到听觉神经元仿真电路中。同时记录应用于仿真电路的激励信号的峰值和从这些模拟电路的输出测量的动态响应的触发时间。然后，利用“动态时间扭曲”算法确定刺激峰值与神经元放电响应的时间差，并根据这一定量测量结果比较这些模拟模拟器的输入/输出同步性能。

{"title":"Analog emulator designs for the auditory neurons and their performance comparison with the dynamic time warping algorithm","authors":"Nimet Korkmaz, Mustafa Molu","doi":"10.1016/j.apacoust.2025.111173","DOIUrl":"10.1016/j.apacoust.2025.111173","url":null,"abstract":"<div><div>In auditory system, after the frequencies of sound signals are modulated by the basilar membrane, these sounds of different frequencies are processed by different auditory neurons. Design of the broadband electronic circuits is a critical issue to emulate the auditory neurons, because these emulator circuit processes the sound signal of various frequency without require any update. In this study, it is aimed to compare the response performance of the auditory neuron emulator circuits that are built by several analog devices. In this context, an auditory neuron model, which is defined by adapting the vibrations in a piezoelectric ceramic to the FitzHugh–Nagumo neuron model, is successfully implemented with voltage operational amplifier, operational transconductance amplifiers, current feedback operational amplifiers and field programmable analog arrays. After the notes of a musical composition are coded in a microcontroller, its electrical signal output is applied to the auditory neuron emulator circuits as an external excitation signal. The peaks of the excitation signal applying to the emulator circuits and the firing times of the dynamic responses measuring from the outputs of these analog circuits are recorded simultaneously. Then, time differences between stimulus peaks and neuronal firing responses are determined with the “Dynamic Time Warping” algorithm and the input/output synchronization performances of these analog emulators are compared according to the result of this quantitative measurement.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"244 ","pages":"Article 111173"},"PeriodicalIF":3.4,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618551","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}

引用次数: 0

Acoustic reflection modeling and experimental study of rough fractal interfaces for dry-coupled ultrasonic testing 干耦合超声检测粗糙分形界面声反射建模及实验研究

IF 3.4 2区物理与天体物理 Q1 ACOUSTICS

Applied Acoustics

Pub Date : 2025-11-28 DOI: 10.1016/j.apacoust.2025.111174

Yuanyao Hu , Donglin Tang , Sheng Rao , Chao Ding , Weiping Wu

This study investigates the enhancement of acoustic performance in ultrasonic dry coupling for solid rough interfaces, focusing on the coupling characteristics of ultrasound propagation through rough contact interfaces. A dry coupling acoustic model is developed based on the Distributed Spring Model (DSM), and a contact stiffness expression incorporating the fractal dimension is derived. Numerical simulations are conducted to analyze the relationship between interface coupling stiffness and load, and a piecewise mapping method is proposed to provide a quantitative basis for precise external load setting. To validate the theoretical model, an ultrasonic dry coupling experimental platform was constructed. The experimental results show that applying an appropriate external load improves the acoustic coupling effect, and the higher the fractal dimension, the lower the load required to achieve ideal coupling. Compared to traditional roughness parameters, the fractal dimension significantly improves measurement stability, reducing the standard deviation by 79.3%. Using the portable dry coupling wheel probe for thickness reduction measurement and applying the fractal dimension method, the minimum load required for optimal coupling was determined. The actual measurement error was maintained within 3%, confirming the feasibility of dry coupling technology for damage detection. Therefore, this study provides theoretical support and a quantitative reference for the performance optimization of dry coupling ultrasonic testing systems.

本文研究了固体粗糙界面下超声干耦合对声学性能的增强，重点研究了超声通过粗糙接触界面传播的耦合特性。基于分布式弹簧模型（DSM）建立了干耦合声学模型，推导了包含分形维数的接触刚度表达式。通过数值模拟分析了界面耦合刚度与载荷之间的关系，提出了分段映射法，为外载荷的精确设置提供了定量依据。为了验证理论模型，搭建了超声干耦合实验平台。实验结果表明，施加适当的外载荷可以改善声耦合效果，分形维数越高，实现理想耦合所需的载荷越低。与传统粗糙度参数相比，分形维数显著提高了测量稳定性，标准差降低79.3%。采用便携式干式耦合轮测厚仪进行减厚测量，并应用分形维数法确定了最优耦合所需的最小载荷。实际测量误差保持在3%以内，证实了干耦合技术用于损伤检测的可行性。因此，本研究为干耦合超声检测系统的性能优化提供了理论支持和定量参考。

{"title":"Acoustic reflection modeling and experimental study of rough fractal interfaces for dry-coupled ultrasonic testing","authors":"Yuanyao Hu , Donglin Tang , Sheng Rao , Chao Ding , Weiping Wu","doi":"10.1016/j.apacoust.2025.111174","DOIUrl":"10.1016/j.apacoust.2025.111174","url":null,"abstract":"<div><div>This study investigates the enhancement of acoustic performance in ultrasonic dry coupling for solid rough interfaces, focusing on the coupling characteristics of ultrasound propagation through rough contact interfaces. A dry coupling acoustic model is developed based on the Distributed Spring Model (DSM), and a contact stiffness expression incorporating the fractal dimension is derived. Numerical simulations are conducted to analyze the relationship between interface coupling stiffness and load, and a piecewise mapping method is proposed to provide a quantitative basis for precise external load setting. To validate the theoretical model, an ultrasonic dry coupling experimental platform was constructed. The experimental results show that applying an appropriate external load improves the acoustic coupling effect, and the higher the fractal dimension, the lower the load required to achieve ideal coupling. Compared to traditional roughness parameters, the fractal dimension significantly improves measurement stability, reducing the standard deviation by 79.3%. Using the portable dry coupling wheel probe for thickness reduction measurement and applying the fractal dimension method, the minimum load required for optimal coupling was determined. The actual measurement error was maintained within 3%, confirming the feasibility of dry coupling technology for damage detection. Therefore, this study provides theoretical support and a quantitative reference for the performance optimization of dry coupling ultrasonic testing systems.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"244 ","pages":"Article 111174"},"PeriodicalIF":3.4,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618550","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}

引用次数: 0