Pub Date : 2017-09-01DOI: 10.1142/S0218396X17500084
Wonseok Yang, Junhong Park
This study presents a simulation of interactions between sound and a surrounding pipe structure conveying fluid flows. A sound-attenuating structure using layered metamaterials of cylindrical shells is proposed and verified. Numerical simulations based on the finite difference method after considering steady fluid flow in the pipe were performed. The effective wave speed and density of the fluid required to determine acoustic characteristics were calculated from the transfer matrix method. This enabled estimation of noise reduction capability. The metastructure layers were lined parallel to the pipe walls to minimize flow resistance. The effective density was negative near the resonance frequency of the layers. The transmission loss predicted for a moving fluid medium was smaller than that for a stationary medium due to boundary layer formation. The proposed method can be used to design silencers to reduce the transmitted noise in pipe systems.
{"title":"Attenuation of Sounds in a Pipe with Shear Flow Using Layered Metamaterials","authors":"Wonseok Yang, Junhong Park","doi":"10.1142/S0218396X17500084","DOIUrl":"https://doi.org/10.1142/S0218396X17500084","url":null,"abstract":"This study presents a simulation of interactions between sound and a surrounding pipe structure conveying fluid flows. A sound-attenuating structure using layered metamaterials of cylindrical shells is proposed and verified. Numerical simulations based on the finite difference method after considering steady fluid flow in the pipe were performed. The effective wave speed and density of the fluid required to determine acoustic characteristics were calculated from the transfer matrix method. This enabled estimation of noise reduction capability. The metastructure layers were lined parallel to the pipe walls to minimize flow resistance. The effective density was negative near the resonance frequency of the layers. The transmission loss predicted for a moving fluid medium was smaller than that for a stationary medium due to boundary layer formation. The proposed method can be used to design silencers to reduce the transmitted noise in pipe systems.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750008"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43290229","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}
Pub Date : 2017-06-01DOI: 10.1142/S0218396X17500011
Kunde Yang, Hui Li, Rui Duan, Qiulong Yang
The interference characteristics of cross-correlated broadband fields received by a single hydrophone deployed near the bottom at two different ranges are analyzed in this paper. The ray theory is used to derive the interference pattern, which is a combination of two kinds of interference phenomena. One kind of interference period contains the information of radial source velocity, and the other one is related to source depth. The source motion parameters, including the range and time of closet point of approach (CPA), constant source velocity and source depth, can be estimated by computing the Fourier transform of cross-correlated broadband fields when the existence of a CPA is apparent in the data. If the CPA is not evident, only the radial source velocity and the discrimination of surface versus submerged source can be provided. Note that the proposed method is a broadband technique. Experimental results confirm this single hydrophone estimation method of radial source velocity and source depth.
{"title":"Analysis on the Characteristic of Cross-Correlated Field and Its Potential Application on Source Localization in Deep Water","authors":"Kunde Yang, Hui Li, Rui Duan, Qiulong Yang","doi":"10.1142/S0218396X17500011","DOIUrl":"https://doi.org/10.1142/S0218396X17500011","url":null,"abstract":"The interference characteristics of cross-correlated broadband fields received by a single hydrophone deployed near the bottom at two different ranges are analyzed in this paper. The ray theory is used to derive the interference pattern, which is a combination of two kinds of interference phenomena. One kind of interference period contains the information of radial source velocity, and the other one is related to source depth. The source motion parameters, including the range and time of closet point of approach (CPA), constant source velocity and source depth, can be estimated by computing the Fourier transform of cross-correlated broadband fields when the existence of a CPA is apparent in the data. If the CPA is not evident, only the radial source velocity and the discrimination of surface versus submerged source can be provided. Note that the proposed method is a broadband technique. Experimental results confirm this single hydrophone estimation method of radial source velocity and source depth.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750001"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43952299","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}
Pub Date : 2017-06-01DOI: 10.1142/s0218396x17920011
V. Henríquez, P. R. Andersen, J. S. Jensen, P. Juhl, J. Sánchez-Dehesa
{"title":"Erratum: A Numerical Model of an Acoustic Metamaterial Using the Boundary Element Method Including Viscous and Thermal Losses (vol 25, 1792001, 2017)","authors":"V. Henríquez, P. R. Andersen, J. S. Jensen, P. Juhl, J. Sánchez-Dehesa","doi":"10.1142/s0218396x17920011","DOIUrl":"https://doi.org/10.1142/s0218396x17920011","url":null,"abstract":"","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1792001"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s0218396x17920011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45287465","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}
Pub Date : 2017-06-01DOI: 10.1142/S0218396X17500023
Shi-Ping Wang
This paper investigates the prediction of the far-field performances of high frequency projectors using the second source array method (SSAM). The far-field parameters can be calculated accurately using the complex acoustic pressure data of two very close parallel planes which lie in the near-field region of the projector. The paper simulates the feasibility of predicting the far-field parameters such as transmitting voltage response and the far-field directivity pattern. The predicting results are compared with that calculated using boundary element method (BEM). It shows very good agreement between the two methods. A planar high frequency projector is measured using the near-field method. In order to verify the predicting results, the far-field measurement is performed for the same projector. The comparison of the results shows that the near-field method is capable to precisely predict the far-field parameters of the projector.
{"title":"Far-Field Performances Prediction of High Frequency Projectors Using Secondary Source Array Method","authors":"Shi-Ping Wang","doi":"10.1142/S0218396X17500023","DOIUrl":"https://doi.org/10.1142/S0218396X17500023","url":null,"abstract":"This paper investigates the prediction of the far-field performances of high frequency projectors using the second source array method (SSAM). The far-field parameters can be calculated accurately using the complex acoustic pressure data of two very close parallel planes which lie in the near-field region of the projector. The paper simulates the feasibility of predicting the far-field parameters such as transmitting voltage response and the far-field directivity pattern. The predicting results are compared with that calculated using boundary element method (BEM). It shows very good agreement between the two methods. A planar high frequency projector is measured using the near-field method. In order to verify the predicting results, the far-field measurement is performed for the same projector. The comparison of the results shows that the near-field method is capable to precisely predict the far-field parameters of the projector.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750002"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46852591","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}
Pub Date : 2017-05-16DOI: 10.1142/S0218396X17500369
Chuanlin He, Kunde Yang, Yuanliang Ma, Bo Lei
Forward-scattered waves are often interfered with and overwhelmed by direct blasts when a submerged target crosses the source–receiver line. The approach named low Doppler analysis and recording gram (LODARGRAM) is developed to separate forward-scattered waves from direct blasts in the Doppler domain. This separation, which is based on the kinetic characteristic of the target and the procedure, is conducted using a sliding Blackman window combined with fast Fourier transform. The concept along with its application is validated using the data collected in a tank experiment. The moving target is recognized and identified by a tilt striation on LODARGRAM. Limitations of the LODARGRAM approach are also discussed.
{"title":"A Direct Approach to Separate Forward-Scattered Waves from the Direct Blast in Doppler Domain for Forward-Scattering Detection","authors":"Chuanlin He, Kunde Yang, Yuanliang Ma, Bo Lei","doi":"10.1142/S0218396X17500369","DOIUrl":"https://doi.org/10.1142/S0218396X17500369","url":null,"abstract":"Forward-scattered waves are often interfered with and overwhelmed by direct blasts when a submerged target crosses the source–receiver line. The approach named low Doppler analysis and recording gram (LODARGRAM) is developed to separate forward-scattered waves from direct blasts in the Doppler domain. This separation, which is based on the kinetic characteristic of the target and the procedure, is conducted using a sliding Blackman window combined with fast Fourier transform. The concept along with its application is validated using the data collected in a tank experiment. The moving target is recognized and identified by a tilt striation on LODARGRAM. Limitations of the LODARGRAM approach are also discussed.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"1 1","pages":"1750036"},"PeriodicalIF":0.0,"publicationDate":"2017-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500369","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42323889","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}
Ocean ambient noise spectrum is one of the most important characteristics of ambient noise. An ocean vector ambient noise field model was built up based on parabolic equation in this paper. Then th...
{"title":"Vector Ocean Ambient Noise Spectrum Simulation Based on Parabolic Equation Model in Shallow Water","authors":"Liufang Fu, Peng Li, Xinhua Zhang, Shuqing Ma, Chengzhi Gao","doi":"10.1142/S0218396X17500345","DOIUrl":"https://doi.org/10.1142/S0218396X17500345","url":null,"abstract":"Ocean ambient noise spectrum is one of the most important characteristics of ambient noise. An ocean vector ambient noise field model was built up based on parabolic equation in this paper. Then th...","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"25 1","pages":"1750034"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500345","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41437967","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}
Pub Date : 2017-03-31DOI: 10.1142/S0218396X17500308
V. Hernández, J. Estrada, E. Moreno, S. Rodriguez, A. Mansur
Ultrasonic guided waves propagating along large structures have great potential as a nondestructive evaluation method. In this context, it is very important to obtain the dispersion curves, which depend on the cross-section of the structure. In this paper, we compute dispersion curves along infinite isotropic plate-like structures using the semi-analytical method (SAFEM) with an isogeometric approach based on B-spline functions. The SAFEM method leads to a family of generalized eigenvalue problems depending on the wave number. For a prescribed wave number, the solution of this problem consists of the nodal displacement vector and the frequency of the guided wave. In this work, the results obtained with B-splines shape functions are compared to the numerical SAFEM solution with quadratic Lagrange shape functions. Advantages of the isogeometric approach are highlighted and include the smoothness of the displacement field components and the computational cost of solving the corresponding generalized eigenval...
{"title":"Numerical Solution of a Wave Propagation Problem Along Plate Structures Based on the Isogeometric Approach","authors":"V. Hernández, J. Estrada, E. Moreno, S. Rodriguez, A. Mansur","doi":"10.1142/S0218396X17500308","DOIUrl":"https://doi.org/10.1142/S0218396X17500308","url":null,"abstract":"Ultrasonic guided waves propagating along large structures have great potential as a nondestructive evaluation method. In this context, it is very important to obtain the dispersion curves, which depend on the cross-section of the structure. In this paper, we compute dispersion curves along infinite isotropic plate-like structures using the semi-analytical method (SAFEM) with an isogeometric approach based on B-spline functions. The SAFEM method leads to a family of generalized eigenvalue problems depending on the wave number. For a prescribed wave number, the solution of this problem consists of the nodal displacement vector and the frequency of the guided wave. In this work, the results obtained with B-splines shape functions are compared to the numerical SAFEM solution with quadratic Lagrange shape functions. Advantages of the isogeometric approach are highlighted and include the smoothness of the displacement field components and the computational cost of solving the corresponding generalized eigenval...","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"1 1","pages":"1750030"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48512362","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}
Pub Date : 2017-03-31DOI: 10.1142/S0218396X17500333
Jiangang Xie, Mingwei Zhuang, Zichao Guo, Hai Liu, Q. Liu
Reverse time migration (RTM), especially that for elastic waves, consumes massive computation resources which limit its wide applications in industry. We suggest to use the pseudospectral time-domain (PSTD) method in elastic wave RTM. RTM using PSTD can significantly reduce the computational requirements compared with RTM using the traditional finite difference time domain method (FDTD). In addition to the advantage of low sampling rate with high accuracy, the PSTD method also eliminates the periodicity (or wraparround) limitation caused by fast Fourier transform in the conventional pseudospectral method. To achieve accurate results, the PSTD method needs only about half the spatial sampling rate of the twelfth-order FDTD method. Thus, the PSTD method can save up to 87.5% storage memory and 90% computation time over the twelfth-order FDTD method. We implement RTM using PSTD for elastic wave equations and accelerate it by Open Multi-Processing technology. To keep the computational load balance in parallel ...
{"title":"Reverse Time Migration of Elastic Waves Using the Pseudospectral Time-Domain Method","authors":"Jiangang Xie, Mingwei Zhuang, Zichao Guo, Hai Liu, Q. Liu","doi":"10.1142/S0218396X17500333","DOIUrl":"https://doi.org/10.1142/S0218396X17500333","url":null,"abstract":"Reverse time migration (RTM), especially that for elastic waves, consumes massive computation resources which limit its wide applications in industry. We suggest to use the pseudospectral time-domain (PSTD) method in elastic wave RTM. RTM using PSTD can significantly reduce the computational requirements compared with RTM using the traditional finite difference time domain method (FDTD). In addition to the advantage of low sampling rate with high accuracy, the PSTD method also eliminates the periodicity (or wraparround) limitation caused by fast Fourier transform in the conventional pseudospectral method. To achieve accurate results, the PSTD method needs only about half the spatial sampling rate of the twelfth-order FDTD method. Thus, the PSTD method can save up to 87.5% storage memory and 90% computation time over the twelfth-order FDTD method. We implement RTM using PSTD for elastic wave equations and accelerate it by Open Multi-Processing technology. To keep the computational load balance in parallel ...","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"1 1","pages":"1750033"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500333","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47162396","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}
Pub Date : 2017-03-31DOI: 10.1142/S0218396X1750031X
Chunhua Deng, M. Luo, M. Yuan, Bo Zhao, Mingwei Zhuang, Q. Liu
The perfectly matched layer (PML) absorbing boundary condition has been proven to absorb body waves and surface waves very efficiently at non-grazing incidence. However, the traditional PML would generate large spurious reflections at grazing incidence, for example, when the sources are located near the truncating boundary and the receivers are at a large offset. In this paper, a new PML implementation is presented for the boundary truncation in three-dimensional spectral element time domain (SETD) for solving acoustic wave equations. This method utilizes pseudospectral time-domain (PSTD) method to solve first-order auxiliary differential equations (ADEs), which is more straightforward than that in the classical FEM framework.
{"title":"The Auxiliary Differential Equations Perfectly Matched Layers Based on the Hybrid SETD and PSTD Algorithms for Acoustic Waves","authors":"Chunhua Deng, M. Luo, M. Yuan, Bo Zhao, Mingwei Zhuang, Q. Liu","doi":"10.1142/S0218396X1750031X","DOIUrl":"https://doi.org/10.1142/S0218396X1750031X","url":null,"abstract":"The perfectly matched layer (PML) absorbing boundary condition has been proven to absorb body waves and surface waves very efficiently at non-grazing incidence. However, the traditional PML would generate large spurious reflections at grazing incidence, for example, when the sources are located near the truncating boundary and the receivers are at a large offset. In this paper, a new PML implementation is presented for the boundary truncation in three-dimensional spectral element time domain (SETD) for solving acoustic wave equations. This method utilizes pseudospectral time-domain (PSTD) method to solve first-order auxiliary differential equations (ADEs), which is more straightforward than that in the classical FEM framework.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"1 1","pages":"1750031"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X1750031X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49622811","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}
Pub Date : 2017-03-31DOI: 10.1142/S0218396X17500321
R. Gilbert, Fachbereich Bauingenier, Doo-sung Lee
In this paper, we continue our work on the propagation of Lamb waves in a poroelastic infinite strip containing a linear crack. In the previous work, the crack was placed horizontal to the upper and lower surfaces and moreover, there was zero pressure on the upper and lower surfaces, a physically impossible situation. In the present paper, the crack is situated perpendicular to the side and situated at the origin. A step stress is applied to the crack surface resulting in transient behavior. By using the Fourier transform and Laplace transform methods, we arrive at dual integral equations. From this formulation, we subsequently obtain, by reduction, a Fredholm integral equation of the second kind. This equation is solved numerically, and the dynamic stress intensity factor is shown graphically.
{"title":"Lamb Waves in a Perpendicularly Cracked, Poroelastic Plate","authors":"R. Gilbert, Fachbereich Bauingenier, Doo-sung Lee","doi":"10.1142/S0218396X17500321","DOIUrl":"https://doi.org/10.1142/S0218396X17500321","url":null,"abstract":"In this paper, we continue our work on the propagation of Lamb waves in a poroelastic infinite strip containing a linear crack. In the previous work, the crack was placed horizontal to the upper and lower surfaces and moreover, there was zero pressure on the upper and lower surfaces, a physically impossible situation. In the present paper, the crack is situated perpendicular to the side and situated at the origin. A step stress is applied to the crack surface resulting in transient behavior. By using the Fourier transform and Laplace transform methods, we arrive at dual integral equations. From this formulation, we subsequently obtain, by reduction, a Fredholm integral equation of the second kind. This equation is solved numerically, and the dynamic stress intensity factor is shown graphically.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"1 1","pages":"1750032"},"PeriodicalIF":0.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X17500321","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42262607","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}
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