{"title":"Diffusion Equation-Based Finite Element Modeling of a Monumental Worship Space","authors":"Zühre Sü Gül, N. Xiang, M. Çaliskan","doi":"10.1142/S0218396X17500291","DOIUrl":"https://doi.org/10.1142/S0218396X17500291","url":null,"abstract":"In this work, a diffusion equation model (DEM) is applied to a room acoustics case for in-depth sound field analysis. Background of the theory, the governing and boundary equations specifically applicable to this study are presented. A three-dimensional geometric model of a monumental worship space is composed. The DEM is solved over this model in a finite element framework to obtain sound energy densities. The sound field within the monument is numerically assessed; spatial sound energy distributions and flow vector analysis are conducted through the time-dependent DEM solutions.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750029"},"PeriodicalIF":0.0,"publicationDate":"2017-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500291","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45153025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Acoustic Imaging with Compressed Sensing and Microphone Arrays","authors":"Fangli Ning, Yong Liu, Chao Zhang, Jingang Wei, Xudong Shi, Juan Wei","doi":"10.1142/S0218396X17500278","DOIUrl":"https://doi.org/10.1142/S0218396X17500278","url":null,"abstract":"This work studies the acoustic imaging problem with compressed sensing (CS) and microphone arrays. The CS algorithm with Basis Pursuit (BP) algorithm has shown satisfying results in acoustic imaging, the maps of which are characterized by super-resolution. However, the performance of the CS algorithm with the BP algorithm is limited to Restricted Isometry Property (RIP), and the algorithm has a long CPU-time. We propose a new CS algorithm with Orthogonal Matching Pursuit (OMP) algorithm for acoustic imaging. The performance of the OMP algorithm with regard to RIP is examined through numerical simulation in this work. The simulation results and CPU-time for OMP algorithm are compared with those of the BP algorithm and the conventional beamformer (CBF). When the RIP does not hold, satisfying results can still be obtained by the OMP algorithm, and the CPU-time for OMP algorithm is far less than BP algorithm. In order to validate the feasibility of the OMP algorithm in acoustic imaging, an experiment is also ...","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750027"},"PeriodicalIF":0.0,"publicationDate":"2017-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500278","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43724368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Juhl, V. Henríquez, P. R. Andersen, J. S. Jensen, J. Sánchez-Dehesa
{"title":"A numerical model of an acoustic metamaterial using the boundary element method including viscous and thermal losses","authors":"P. Juhl, V. Henríquez, P. R. Andersen, J. S. Jensen, J. Sánchez-Dehesa","doi":"10.1142/S0218396X17500060","DOIUrl":"https://doi.org/10.1142/S0218396X17500060","url":null,"abstract":"In recent years, boundary element method (BEM) and finite element method (FEM) implementations of acoustics in fluids with viscous and thermal losses have been developed. They are based on the linearized Navier–Stokes equations with no flow. In this paper, such models with acoustic losses are applied to an acoustic metamaterial. Metamaterials are structures formed by smaller, usually periodic, units showing remarkable physical properties when observed as a whole. Acoustic losses are relevant in metamaterials in the millimeter scale. In addition, their geometry is intricate and challenging for numerical implementation. The results are compared with existing measurements.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750006"},"PeriodicalIF":0.0,"publicationDate":"2017-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44093131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Infinite Elements and Their Influence on Normal and Radiation Modes in Exterior Acoustics","authors":"Lennart Moheit, S. Marburg","doi":"10.1142/S0218396X1650020X","DOIUrl":"https://doi.org/10.1142/S0218396X1650020X","url":null,"abstract":"Acoustic radiation modes (ARMs) and normal modes (NMs) are calculated at the surface of a fluid-filled domain around a solid structure and inside the domain, respectively. In order to compute the e...","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1650020"},"PeriodicalIF":0.0,"publicationDate":"2017-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X1650020X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48250595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Acoustical Green’s Function and Boundary Element Techniques for 3D Half-Space Problems","authors":"R. Piscoya, M. Ochmann","doi":"10.1142/S0218396X17300018","DOIUrl":"https://doi.org/10.1142/S0218396X17300018","url":null,"abstract":"This paper presents a review of basic concepts of the boundary element method (BEM) for solving 3D half-space problems in a homogeneous medium and in frequency domain. The usual BEM for exterior problems can be extended easily for half-space problems only if the infinite plane is either rigid or soft, since the necessary tailored Green’s function is available. The difficulties arise when the infinite plane has finite impedance. Numerous expressions for the Green’s function have been found which need to be computed numerically. The practical implementation of some of these formulas shows that their application depends on the type of impedance of the plane. In this work, several formulas in frequency domain are discussed. Some of them have been implemented in a BEM formulation and results of their application in specific numerical examples are summarized. As a complement, two formulas of the Green’s function in time domain are presented. These formulas have been computed numerically and after the applicatio...","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1730001"},"PeriodicalIF":0.0,"publicationDate":"2017-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17300018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43882929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonlinear Distortion Characteristic Analysis for the Finite Amplitude Sound Pressures in the Pistonphone","authors":"Fan Zhang, Wen He, Zhong Junjie","doi":"10.1142/S0218396X1850008X","DOIUrl":"https://doi.org/10.1142/S0218396X1850008X","url":null,"abstract":"The wide concern on absolute calibration of microphones at high pressure levels prompts the development of the pistonphone technique. However, as the sound pressure level goes higher, the linear hypothesis, which is applicable for the small amplitude sound wave, will no longer be valid. The nonlinear characteristics of the finite amplitude sound wave will produce high order harmonic components and also some other complex frequency components, which eventually result in the distortion of the sound pressure in the pistonphone, and should be quantitatively calculated to assess the accuracy of absolute sound pressure calibration of microphones at high sound pressure levels using pistonphones. In this paper, the linearized wave equations were built based on the perturbation method and the Euler system. Then, the distributed parameter expressions for the finite amplitude sound pressure both neglecting and considering the intermodulation characteristic have been explicitly derived. Nonlinear distortion character...","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1850008"},"PeriodicalIF":0.0,"publicationDate":"2017-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X1850008X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43321664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Fourier Collocation Approach for Transit-Time Ultrasonic Flowmeter Under Multi-Phase Flow Conditions","authors":"M. Simurda, B. Lassen, L. Duggen, N. Basse","doi":"10.1142/S0218396X17500059","DOIUrl":"https://doi.org/10.1142/S0218396X17500059","url":null,"abstract":"A numerical model for a clamp-on transit-time ultrasonic flowmeter (TTUF) under multi-phase flow conditions is presented. The method solves equations of linear elasticity for isotropic heterogeneous materials with background flow where acoustic media are modeled by setting shear modulus to zero. Spatial derivatives are calculated by a Fourier collocation method allowing the use of the fast Fourier transform (FFT) and time derivatives are approximated by a finite difference (FD) scheme. This approach is sometimes referred to as a pseudospectral time-domain method. Perfectly matched layers (PML) are used to avoid wave-wrapping and staggered grids are implemented to improve stability and efficiency. The method is verified against exact analytical solutions and the effect of the time-staggering and associated lowest number of points per minimum wavelengths value is discussed. The method is then employed to model a complete TTUF measurement setup to simulate the effect of a flow profile on the flowmeter accuracy and a study of an impact of inclusions in flowing media on received signals is carried out.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750005"},"PeriodicalIF":0.0,"publicationDate":"2017-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500059","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45907649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Interval Reduced Basis Approach and its Integrated Framework for Acoustic Response Analysis of Coupled Structural-Acoustic System","authors":"Lv Zheng, Qiu Zhiping, Li Qi","doi":"10.1142/S0218396X17500096","DOIUrl":"https://doi.org/10.1142/S0218396X17500096","url":null,"abstract":"An interval reduced basis approach (IRBA) is presented for analyzing acoustic response of coupled structural-acoustic system with interval parameters. Simultaneously an integrated framework based on IRBA is established to deal with uncertain acoustic propagation using deterministic finite element (FE) software. The present IRBA aims to improve the accuracy of the conventional first-order approximation and also allow the efficient calculation of second-order approximation of acoustic response. In IRBA, acoustic response is approximated using a linear combination of interval basis vectors with undetermined coefficients. To get explicit expression of acoustic response in terms of interval parameters, the three terms of the second-order perturbation method are employed as basis vectors, and the variant of the Galerkin scheme is applied for derivation of the reduced-order system of equations. For the second-order approximation, the determination of acoustic response interval is reformulated into a series of quadratic programming problems, which are solved using the difference of convex functions (DC) algorithm effectively. The performance of IRBA and availability of the present framework are validated by numerical examples.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750009"},"PeriodicalIF":0.0,"publicationDate":"2017-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41938309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sensitivity to High Frequency Communication Sounds in the Inner Ear Enhanced by Selective Attention: Preliminary Findings in Mongolian Gerbils","authors":"Ayako Nakayama, H. Riquimaroux","doi":"10.1142/S0218396X17500163","DOIUrl":"https://doi.org/10.1142/S0218396X17500163","url":null,"abstract":"Audible range for Mongolian gerbils overlaps well with one for humans. This is one of the reasons why they have been used for auditory studies. So, most of studies on gerbils have been in human audible frequency range. They live in a group and use a variety of vocalizations for their conspecific communication. Roughly 80% of the fundamental frequencies of their communication calls are found in the frequency range above 20kHz. However, thresholds for frequencies above 20kHz have been reported higher than those for low frequencies (from 1kHz to 16kHz) by as much as 20dB. We examined how gerbils utilize ultrasonic frequency range for their important vocal communication. Findings from alert animals with paired condition showed the cochlear microphonics (CM) were amplified by 2–4dB with ultrasonic communication calls of low sound pressure levels (from 45dB to 60dB p.e. SPL), while no enhancement was observed with the same calls higher than 65dB p.e. SPL. Findings also suggested that CM responses to tone burst higher than 25kHz demonstrated magnified amplitude under the paired condition. Data strongly imply that attention to conspecifics would increase sensitivity to ultrasonic frequency range.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750016"},"PeriodicalIF":0.0,"publicationDate":"2017-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500163","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44631510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bayesian Inversion for Geoacoustic Parameters from Ocean Bottom Reflection Loss","authors":"Kunde Yang, Peng Xiao, Rui Duan, Yuanliang Ma","doi":"10.1142/S0218396X17500199","DOIUrl":"https://doi.org/10.1142/S0218396X17500199","url":null,"abstract":"Geoacoustic inversion is a very important issue in underwater acoustics, and the inversion method based on bottom reflection loss is a valid technique to invert bottom parameters. This paper describes a Bayesian method for estimating bottom parameters in the deep ocean based on inversion of reflection loss versus angle data which were obtained from an experiment conducted in South China Sea in 2013. The experimental data show that bottom loss depends on frequency. The Bayesian method can be applied in nonlinear inversion problems, and it provides useful indication about the quality of the inversion and parameter sensitivities. The bottom is modeled as a two-layer model, and each layer has constant parameters. The inverted parameters of sediment show a clay feature which is consistent with the core data. Furthermore, the inversion results are used to calculate transmission losses (TLs) along the experiment track which agree well with the direct measurements. Although the inversion results are limited to reveal exact structures of bottom, they are still useful for forecasting propagation losses in this area.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750019"},"PeriodicalIF":0.0,"publicationDate":"2017-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500199","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48445519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}