Pub Date : 2015-06-25DOI: 10.1142/S0218396X15500149
K. Szemela
The sound radiation inside an acoustic canyon has been analyzed for a surface sound source located at the bottom. Based on rigorous mathematical manipulations, the formulas of a high computational efficiency describing the sound pressure and sound power have been obtained. They can be easily adapted to describe the sound radiation of an arbitrary system of sound sources. As an example of their application, the sound radiation of a piston has been investigated. The asymptotic formulas of the sound power modal coefficients have been obtained. They can be used to significantly improve the numerical calculation of the sound power.
{"title":"Sound Radiation Inside an Acoustic Canyon with a Surface Sound Source Located at the Bottom","authors":"K. Szemela","doi":"10.1142/S0218396X15500149","DOIUrl":"https://doi.org/10.1142/S0218396X15500149","url":null,"abstract":"The sound radiation inside an acoustic canyon has been analyzed for a surface sound source located at the bottom. Based on rigorous mathematical manipulations, the formulas of a high computational efficiency describing the sound pressure and sound power have been obtained. They can be easily adapted to describe the sound radiation of an arbitrary system of sound sources. As an example of their application, the sound radiation of a piston has been investigated. The asymptotic formulas of the sound power modal coefficients have been obtained. They can be used to significantly improve the numerical calculation of the sound power.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550014"},"PeriodicalIF":0.0,"publicationDate":"2015-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500149","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076572","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 : 2015-06-25DOI: 10.1142/S0218396X15500058
M. Ballard, B. Goldsberry, M. Isakson
Three-dimensional propagation over an infinitely long cosine shaped hill is examined using an approximate normal mode/parabolic equation hybrid model that includes mode coupling in the out-going direction. The slope of the hill is relatively shallow, but it is significant enough to produce both mode-coupling and horizontal refraction effects. In the first part of the paper, the modeling approach is described, and the solution is compared to results obtained with a finite element method to evaluate the accuracy of the solution in light of assumptions made in formulating the model. Then the calculated transmission loss is interpreted in terms of a modal decomposition of the field, and the solution from the hybrid model is compared to adiabatic and N × 2D solutions to assess the relative importance of horizontal refraction and mode-coupling effects. An analysis using a horizontal ray trace is presented to explain differences in the modal interference pattern observed between the 3D and N × 2D solutions. The detailed discussion provides a thorough explanation of the observed 3D propagation effects and demonstrates the usefulness of the approximate normal mode/parabolic equation hybrid model as a tool to understand measured transmission loss in complex environments.
{"title":"Normal mode analysis of three-dimensional propagation over a small-slope cosine shaped hill","authors":"M. Ballard, B. Goldsberry, M. Isakson","doi":"10.1142/S0218396X15500058","DOIUrl":"https://doi.org/10.1142/S0218396X15500058","url":null,"abstract":"Three-dimensional propagation over an infinitely long cosine shaped hill is examined using an approximate normal mode/parabolic equation hybrid model that includes mode coupling in the out-going direction. The slope of the hill is relatively shallow, but it is significant enough to produce both mode-coupling and horizontal refraction effects. In the first part of the paper, the modeling approach is described, and the solution is compared to results obtained with a finite element method to evaluate the accuracy of the solution in light of assumptions made in formulating the model. Then the calculated transmission loss is interpreted in terms of a modal decomposition of the field, and the solution from the hybrid model is compared to adiabatic and N × 2D solutions to assess the relative importance of horizontal refraction and mode-coupling effects. An analysis using a horizontal ray trace is presented to explain differences in the modal interference pattern observed between the 3D and N × 2D solutions. The detailed discussion provides a thorough explanation of the observed 3D propagation effects and demonstrates the usefulness of the approximate normal mode/parabolic equation hybrid model as a tool to understand measured transmission loss in complex environments.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550005"},"PeriodicalIF":0.0,"publicationDate":"2015-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500058","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076534","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}
This paper investigates the efficiency of the wave finite element (WFE) method to assess the vibroacoustic behavior of finite baffled axisymmetric elastic pipes interacting with internal and external acoustic fluids. The pipes, of either homogeneous or multi-layered cross-sections, are surrounded by an external fluid of infinite extent, which can be light or heavy. The Sommerfeld radiation condition is taken into account by considering a perfectly matched layer (PML) around the external fluid. The method involves the computation of waves traveling along an axisymmetric multi-physics waveguide that incorporates a pipe, internal and external fluids, as well as a PML. Numerical experiments are carried out which highlight the relevance of the WFE method in terms of accuracy and CPU time savings, in comparison with the conventional finite element analysis.
{"title":"On the Acoustic Radiation of Axisymmetric Fluid-Filled Pipes Using the Wave Finite Element (WFE) Method","authors":"Ajit Bhuddi, Marie-Laure Gobert, Jean-Mathieu Mencik","doi":"10.1142/S0218396X15500113","DOIUrl":"https://doi.org/10.1142/S0218396X15500113","url":null,"abstract":"This paper investigates the efficiency of the wave finite element (WFE) method to assess the vibroacoustic behavior of finite baffled axisymmetric elastic pipes interacting with internal and external acoustic fluids. The pipes, of either homogeneous or multi-layered cross-sections, are surrounded by an external fluid of infinite extent, which can be light or heavy. The Sommerfeld radiation condition is taken into account by considering a perfectly matched layer (PML) around the external fluid. The method involves the computation of waves traveling along an axisymmetric multi-physics waveguide that incorporates a pipe, internal and external fluids, as well as a PML. Numerical experiments are carried out which highlight the relevance of the WFE method in terms of accuracy and CPU time savings, in comparison with the conventional finite element analysis.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550011"},"PeriodicalIF":0.0,"publicationDate":"2015-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500113","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076987","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 : 2015-06-25DOI: 10.1142/S0218396X15500101
Qiaoling Zhang, Zhe Chen, F. Yin
Based on the combination of global coherence field (GCF) and distributed particle filter (DPF) a speaker tracking method is proposed for distributed microphone networks in this paper. In the distributed microphone network, each node comprises a microphone pair, and its generalized cross-correlation (GCC) function is estimated. Based on the average over all local GCC observations, a global coherence field-based pseudo-likelihood (GCF-PL) function is developed as the likelihood for a DPF. In the proposed method, all nodes share an identical particle set, and each node performs local particle filtering simultaneously. In the local particle filter, the likelihood GCF-PL for each particle weight is computed with an average consensus algorithm. With an identical particle set and the consistent estimate of GCF-PL for each particle weight, all individual nodes possess a common particle presentation for the global posterior of the speaker state, which is utilized by each node for an estimated global speaker position. Employing the GCF-PL as the likelihood for DPF, no assumption is required about the independence of nodes observations as well as observation noise statistics. Additionally, only local information exchange occurs among neighboring nodes; and finally each node has a global estimate of the speaker position. Simulation results demonstrate the validity of the proposed method.
{"title":"Global Coherence Field and Distributed Particle Filter-Based Speaker Tracking in Distributed Microphone Networks","authors":"Qiaoling Zhang, Zhe Chen, F. Yin","doi":"10.1142/S0218396X15500101","DOIUrl":"https://doi.org/10.1142/S0218396X15500101","url":null,"abstract":"Based on the combination of global coherence field (GCF) and distributed particle filter (DPF) a speaker tracking method is proposed for distributed microphone networks in this paper. In the distributed microphone network, each node comprises a microphone pair, and its generalized cross-correlation (GCC) function is estimated. Based on the average over all local GCC observations, a global coherence field-based pseudo-likelihood (GCF-PL) function is developed as the likelihood for a DPF. In the proposed method, all nodes share an identical particle set, and each node performs local particle filtering simultaneously. In the local particle filter, the likelihood GCF-PL for each particle weight is computed with an average consensus algorithm. With an identical particle set and the consistent estimate of GCF-PL for each particle weight, all individual nodes possess a common particle presentation for the global posterior of the speaker state, which is utilized by each node for an estimated global speaker position. Employing the GCF-PL as the likelihood for DPF, no assumption is required about the independence of nodes observations as well as observation noise statistics. Additionally, only local information exchange occurs among neighboring nodes; and finally each node has a global estimate of the speaker position. Simulation results demonstrate the validity of the proposed method.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550010"},"PeriodicalIF":0.0,"publicationDate":"2015-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500101","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076909","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 : 2015-06-25DOI: 10.1142/S0218396X15500095
C. P. Gajardo, L. Godinho, P. Amado-Mendes, J. M. B. Morillas
Acoustic barriers are a well-known environmental noise mitigation solution, which is widely used nowadays. In this work, it is expected to contribute to the body of knowledge regarding the physical and technical behavior of those barriers by developing and implementing a set of models that allow an accurate analysis of noise barriers with new configuration types. A 2.5D boundary-only numerical model is developed and implemented, and computational analyses are performed in order to compare different surface profiles of the acoustic barriers. The particular case in which two acoustic barriers are used, one at each side of the road, is addressed.
{"title":"Numerical Analysis of Acoustic Barriers with a Diffusive Surface Using a 2.5D Boundary Element Model","authors":"C. P. Gajardo, L. Godinho, P. Amado-Mendes, J. M. B. Morillas","doi":"10.1142/S0218396X15500095","DOIUrl":"https://doi.org/10.1142/S0218396X15500095","url":null,"abstract":"Acoustic barriers are a well-known environmental noise mitigation solution, which is widely used nowadays. In this work, it is expected to contribute to the body of knowledge regarding the physical and technical behavior of those barriers by developing and implementing a set of models that allow an accurate analysis of noise barriers with new configuration types. A 2.5D boundary-only numerical model is developed and implemented, and computational analyses are performed in order to compare different surface profiles of the acoustic barriers. The particular case in which two acoustic barriers are used, one at each side of the road, is addressed.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"29 1","pages":"1550009"},"PeriodicalIF":0.0,"publicationDate":"2015-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500095","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076754","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 : 2015-06-25DOI: 10.1142/S0218396X15500137
M. Kharrat, M. Ichchou, O. Bareille, Zhou Wenjin
This paper provides a numerical investigation onto the effect of the angular position of a defect on the wave diffusion in a steel pipe. The wave finite element method (WFEM) is used to calculate reflection and transmission coefficients from defects with different angular positions as a function of frequency. The modeled defects are impinged successively by torsional T(0, 1), longitudinal L(0, 2) and flexural F(1, 2) modes. The wave diffusion in each case is examined leading to several important remarks. Results show that the choice of the incident mode as well as the studied reflected and transmitted modes play a crucial role in the circumferential localization of defects in pipes.
{"title":"Wave Diffusion Sensitivity to Angular Positions of Defects in Pipes","authors":"M. Kharrat, M. Ichchou, O. Bareille, Zhou Wenjin","doi":"10.1142/S0218396X15500137","DOIUrl":"https://doi.org/10.1142/S0218396X15500137","url":null,"abstract":"This paper provides a numerical investigation onto the effect of the angular position of a defect on the wave diffusion in a steel pipe. The wave finite element method (WFEM) is used to calculate reflection and transmission coefficients from defects with different angular positions as a function of frequency. The modeled defects are impinged successively by torsional T(0, 1), longitudinal L(0, 2) and flexural F(1, 2) modes. The wave diffusion in each case is examined leading to several important remarks. Results show that the choice of the incident mode as well as the studied reflected and transmitted modes play a crucial role in the circumferential localization of defects in pipes.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550013"},"PeriodicalIF":0.0,"publicationDate":"2015-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500137","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64077037","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 : 2015-05-07DOI: 10.1142/S0218396X15500125
R. Gilbert, Dooyoul Lee
Hydraulic fracking is used in the petroleum industry for the secondary production of either oil or natural gas. Normally a high pressure fluid is injected through a well bore to create cracks or fissures in the oil bearing sediment. Usually small grains of sand are suspended in the fracking fluid and remain after the pressure is released; thereby, allowing the oil or gas to pass more freely through the fissure. Because of the large difference of permeability of the fissure to the oil bearing strata, oil or gas flows easily into the fissure and is easily produced through the well bore. In our model we consider the fractured vein to be approximated by a penny-shaped crack, placed horizontal to the well bore. Because of symmetry conditions, in the case of a gravity drainage model for producing oil, a crack lying at the bottom of the oil bearing strata can be modeled by a sediment of twice that size with a crack lying in the center. For the case of producing natural gas a similar argument may be made. What is of interest to the petroleum industry is to determine the size of the fracture, in our case that would be the radius. This problem may be reformulated as an inverse problem where we attempt to find the radius of the fracture from sonic information, for example, by measuring the scattered Lamb waves which are created by a suddenly imposed stress on the fracture. In the present work we consider the direct problem, namely what are the amplitudes of the scattered wave for known penny-shaped crack. In a subsequent paper we will consider the inversion of the Lamb wave data to reveal the radius of the fissure.
{"title":"Penny-Shaped Crack in a Poroelastic Plate","authors":"R. Gilbert, Dooyoul Lee","doi":"10.1142/S0218396X15500125","DOIUrl":"https://doi.org/10.1142/S0218396X15500125","url":null,"abstract":"Hydraulic fracking is used in the petroleum industry for the secondary production of either oil or natural gas. Normally a high pressure fluid is injected through a well bore to create cracks or fissures in the oil bearing sediment. Usually small grains of sand are suspended in the fracking fluid and remain after the pressure is released; thereby, allowing the oil or gas to pass more freely through the fissure. Because of the large difference of permeability of the fissure to the oil bearing strata, oil or gas flows easily into the fissure and is easily produced through the well bore. In our model we consider the fractured vein to be approximated by a penny-shaped crack, placed horizontal to the well bore. Because of symmetry conditions, in the case of a gravity drainage model for producing oil, a crack lying at the bottom of the oil bearing strata can be modeled by a sediment of twice that size with a crack lying in the center. For the case of producing natural gas a similar argument may be made. What is of interest to the petroleum industry is to determine the size of the fracture, in our case that would be the radius. This problem may be reformulated as an inverse problem where we attempt to find the radius of the fracture from sonic information, for example, by measuring the scattered Lamb waves which are created by a suddenly imposed stress on the fracture. In the present work we consider the direct problem, namely what are the amplitudes of the scattered wave for known penny-shaped crack. In a subsequent paper we will consider the inversion of the Lamb wave data to reveal the radius of the fissure.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550012"},"PeriodicalIF":0.0,"publicationDate":"2015-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64077028","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}
Guided waves sensitivity to environmental and operational conditions, especially temperature fluctuations, is one of the major problems when the method is considered for real engineering applications. The aim of this paper is to propose a novel dispersion curves extraction method for waveguides affected by nonuniform transient temperature field. Essentially, the method is based on a simple and robust approach, consisting in a few series of modal analyses for a representative part of the inspected structure. To consider the effect of temperature, a thermal stress calculation based on finite element method is presented. In this way, for different wave lengths, the mode shapes and corresponding natural frequencies can be obtained by solving some thermal-eigenvalue problems. To test the theoretical thermal effect of the dispersion curves a experiment on an isotropic plate is conducted. Those theoretical dispersion curves, consisting of only dominant modes, are compared with dispersion curves obtained from experiment. Finally, this method is used to extract the dispersion curves of the aero-engine casing considering the nonuniform temperature field. The results not only give us insight to how temperature affects Lamb wave velocities in different frequency ranges but also will help those extracting dispersion curves for waveguides affected by nonuniform transient temperature field.
{"title":"Novel Dispersion Curves Extraction Method for Waveguides Affected by Nonuniform Transient Temperature Field","authors":"Denghong Xiao, Tian He, Xiandong Liu, Yingchun Shan","doi":"10.1142/S0218396X15500071","DOIUrl":"https://doi.org/10.1142/S0218396X15500071","url":null,"abstract":"Guided waves sensitivity to environmental and operational conditions, especially temperature fluctuations, is one of the major problems when the method is considered for real engineering applications. The aim of this paper is to propose a novel dispersion curves extraction method for waveguides affected by nonuniform transient temperature field. Essentially, the method is based on a simple and robust approach, consisting in a few series of modal analyses for a representative part of the inspected structure. To consider the effect of temperature, a thermal stress calculation based on finite element method is presented. In this way, for different wave lengths, the mode shapes and corresponding natural frequencies can be obtained by solving some thermal-eigenvalue problems. To test the theoretical thermal effect of the dispersion curves a experiment on an isotropic plate is conducted. Those theoretical dispersion curves, consisting of only dominant modes, are compared with dispersion curves obtained from experiment. Finally, this method is used to extract the dispersion curves of the aero-engine casing considering the nonuniform temperature field. The results not only give us insight to how temperature affects Lamb wave velocities in different frequency ranges but also will help those extracting dispersion curves for waveguides affected by nonuniform transient temperature field.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550007"},"PeriodicalIF":0.0,"publicationDate":"2015-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500071","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076279","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 : 2015-05-07DOI: 10.1142/S0218396X15500083
M. Bai, Chia-Hao Kuo
This paper examines two fundamental issues in sound field analysis: acoustic sources localization and separation. Algorithms are developed to locate and separate acoustic signals on the basis of plane-wave decomposition. In the localization stage, directions of plane waves are determined using either minimum variance distortionless response (MVDR) method or multiple signal classification (MUSIC) method. For broadband scenarios, coherent and incoherent techniques are utilized in the localization procedure. In the separation stage, two approaches with overdetermined and underdetermined settings can be employed. In the overdetermined approach, Tikhonov regularization (TIKR) is utilized to recover the source signals. In the underdetermined approach, the steering matrix is augmented by including the directions that have been determined in the localization stage. Hence, the separation problem is formulated into a compressive sensing (CS) problem which can be effectively solved by using convex (CVX) optimization. Simulation and experiments are conducted for a 24-element circular array. Objective tests using perceptual evaluation of speech quality (PESQ) tests and subjective listening tests demonstrate that the proposed methods yield speech signals with well separated and improved quality, as compared to the mixed signals.
{"title":"Acoustic Source Localization and Deconvolution-Based Separation","authors":"M. Bai, Chia-Hao Kuo","doi":"10.1142/S0218396X15500083","DOIUrl":"https://doi.org/10.1142/S0218396X15500083","url":null,"abstract":"This paper examines two fundamental issues in sound field analysis: acoustic sources localization and separation. Algorithms are developed to locate and separate acoustic signals on the basis of plane-wave decomposition. In the localization stage, directions of plane waves are determined using either minimum variance distortionless response (MVDR) method or multiple signal classification (MUSIC) method. For broadband scenarios, coherent and incoherent techniques are utilized in the localization procedure. In the separation stage, two approaches with overdetermined and underdetermined settings can be employed. In the overdetermined approach, Tikhonov regularization (TIKR) is utilized to recover the source signals. In the underdetermined approach, the steering matrix is augmented by including the directions that have been determined in the localization stage. Hence, the separation problem is formulated into a compressive sensing (CS) problem which can be effectively solved by using convex (CVX) optimization. Simulation and experiments are conducted for a 24-element circular array. Objective tests using perceptual evaluation of speech quality (PESQ) tests and subjective listening tests demonstrate that the proposed methods yield speech signals with well separated and improved quality, as compared to the mixed signals.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550008"},"PeriodicalIF":0.0,"publicationDate":"2015-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15500083","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076481","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 : 2015-05-07DOI: 10.1142/S0218396X1550006X
Ramin Kaviani, M. Nikkhah-bahrami
In this paper, the three-dimensional Navier–Stokes characteristic boundary conditions for large-eddy and aeroacoustic simulations are extended to curvilinear coordinates formulations. A robust way of treating the transverse and gradient terms on boundary planes is presented which is different from previous generalized characteristic boundary conditions. The performance of the new formulation is examined via four test problems: an inviscid convective vortex, a two-dimensional mixing layer, a Mach 0.75 round jet, and a Mach 0.51 nozzle/jet. For each test problem, the numerical schemes used to implement the boundary conditions, the numerical parameters employed, and the predicted three-dimensional flow fields are presented. Based on the numerical experiments conducted, the new boundary conditions show promise for high-fidelity simulations of compressible viscous flows.
{"title":"Improved Navier–Stokes Boundary Conditions Based on Generalized Characteristics","authors":"Ramin Kaviani, M. Nikkhah-bahrami","doi":"10.1142/S0218396X1550006X","DOIUrl":"https://doi.org/10.1142/S0218396X1550006X","url":null,"abstract":"In this paper, the three-dimensional Navier–Stokes characteristic boundary conditions for large-eddy and aeroacoustic simulations are extended to curvilinear coordinates formulations. A robust way of treating the transverse and gradient terms on boundary planes is presented which is different from previous generalized characteristic boundary conditions. The performance of the new formulation is examined via four test problems: an inviscid convective vortex, a two-dimensional mixing layer, a Mach 0.75 round jet, and a Mach 0.51 nozzle/jet. For each test problem, the numerical schemes used to implement the boundary conditions, the numerical parameters employed, and the predicted three-dimensional flow fields are presented. Based on the numerical experiments conducted, the new boundary conditions show promise for high-fidelity simulations of compressible viscous flows.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1550006"},"PeriodicalIF":0.0,"publicationDate":"2015-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X1550006X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076200","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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