Pub Date : 2001-11-11DOI: 10.1115/imece2001/nca-23514
Michael G. Allen, N. Vlahopoulos
A formulation that accounts for manufacturing variability in the analysis of structural/acoustic systems is presented. The methodology incorporates the concept of fast probability integration with finite element (FEA) and boundary element analysis (BEA) for producing the probabilistic acoustic response of a structural/acoustic system. The advanced mean value method is used for integrating the system probability density function. FEA and BEA are combined for producing the acoustic response that constitutes the performance function. The probabilistic acoustic response is calculated in terms of a cumulative distribution function. The new methodology is used to illustrate the difference between the results from a probabilistic analysis that accounts for manufacturing uncertainty, and an equivalent deterministic simulation through applications. The probabilistic computations are validated by comparison to Monte Carlo simulations. Based on its computational efficiency and its accuracy the new methodology is concluded to be a viable method of calculating numerically the probabilistic response of structural/acoustic systems due to manufacturing variability.
{"title":"Numerical Probabilistic Analysis of Structural/Acoustic Systems","authors":"Michael G. Allen, N. Vlahopoulos","doi":"10.1115/imece2001/nca-23514","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23514","url":null,"abstract":"\u0000 A formulation that accounts for manufacturing variability in the analysis of structural/acoustic systems is presented. The methodology incorporates the concept of fast probability integration with finite element (FEA) and boundary element analysis (BEA) for producing the probabilistic acoustic response of a structural/acoustic system. The advanced mean value method is used for integrating the system probability density function. FEA and BEA are combined for producing the acoustic response that constitutes the performance function. The probabilistic acoustic response is calculated in terms of a cumulative distribution function. The new methodology is used to illustrate the difference between the results from a probabilistic analysis that accounts for manufacturing uncertainty, and an equivalent deterministic simulation through applications. The probabilistic computations are validated by comparison to Monte Carlo simulations. Based on its computational efficiency and its accuracy the new methodology is concluded to be a viable method of calculating numerically the probabilistic response of structural/acoustic systems due to manufacturing variability.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114127774","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23525
P. Driesch, G. Koopmann
A virtual design methodology is developed to minimize the noise in enclosures when coupled to optimally designed systems of passive acoustic absorbers (Helmholtz resonators). This methodology utilizes a computationally efficient modeling technique in order to determine the modified response of a system by modal expansion of the unmodified system eigenvectors. A determination of this type (efficient model/reanalysis approach) significantly increases the design possibilities when current optimization techniques are implemented. This novel methodology is experimentally verified for a 30.5 cm by 40.6 cm by 2.5 cm 2D enclosure coupled to two optimally designed Helmholtz resonators. A 4.2 dB experimental reduction of potential energy averaged over the 300—700 Hz band was obtained.
开发了一种虚拟设计方法，以最大限度地减少与优化设计的被动吸声器(亥姆霍兹谐振器)系统耦合时的外壳噪声。该方法利用计算效率高的建模技术，通过对未修改系统特征向量的模态展开来确定系统的修改响应。这种类型的确定(有效的模型/再分析方法)在实施当前优化技术时显着增加了设计的可能性。该方法在一个30.5 cm × 40.6 cm × 2.5 cm的二维外壳上进行了实验验证，该外壳与两个优化设计的亥姆霍兹谐振器耦合在一起。实验结果表明，在300-700 Hz波段，平均势能降低了4.2 dB。
{"title":"Acoustic Control in a 2D Enclosure Using Two Optimally Designed Helmholtz Resonators","authors":"P. Driesch, G. Koopmann","doi":"10.1115/imece2001/nca-23525","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23525","url":null,"abstract":"\u0000 A virtual design methodology is developed to minimize the noise in enclosures when coupled to optimally designed systems of passive acoustic absorbers (Helmholtz resonators). This methodology utilizes a computationally efficient modeling technique in order to determine the modified response of a system by modal expansion of the unmodified system eigenvectors. A determination of this type (efficient model/reanalysis approach) significantly increases the design possibilities when current optimization techniques are implemented. This novel methodology is experimentally verified for a 30.5 cm by 40.6 cm by 2.5 cm 2D enclosure coupled to two optimally designed Helmholtz resonators. A 4.2 dB experimental reduction of potential energy averaged over the 300—700 Hz band was obtained.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123184634","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23539
J. Vipperman, Deyuan Li, I. Avdeev
The vibroacoustic behavior of an advanced grid-stiffened (AGS) composite structure which is reminiscent of a mock-scale fairing has been investigated. Both finite element analysis (FEA) and experimental modal analysis have been performed and the results corroborated. The lightly-coupled structurally-dominant modes and acoustically-dominant modes can be used to determine the structural acoustic coupling coefficients for the fairing. In addition, the certain critical structural acoustic frequencies have been computed. These results can be assimilated in order to provide insight into the theoretical performance limits of various potential transmission control mechanisms, including geometry or property tuning, the inclusion of passive control materials, or the addition of secondary structural and/or acoustic control inputs.
{"title":"Investigation of the Transmission Loss Behavior of an Advanced Grid-Stiffened Structure","authors":"J. Vipperman, Deyuan Li, I. Avdeev","doi":"10.1115/imece2001/nca-23539","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23539","url":null,"abstract":"\u0000 The vibroacoustic behavior of an advanced grid-stiffened (AGS) composite structure which is reminiscent of a mock-scale fairing has been investigated. Both finite element analysis (FEA) and experimental modal analysis have been performed and the results corroborated. The lightly-coupled structurally-dominant modes and acoustically-dominant modes can be used to determine the structural acoustic coupling coefficients for the fairing. In addition, the certain critical structural acoustic frequencies have been computed. These results can be assimilated in order to provide insight into the theoretical performance limits of various potential transmission control mechanisms, including geometry or property tuning, the inclusion of passive control materials, or the addition of secondary structural and/or acoustic control inputs.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122829603","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23518
V. W. Popham, C. Lawrenson, R. F. Burr, B. Lipkens
Variable gap-reluctance linear motors operate on the principle of electromagnetic attraction across an air gap between a moving armature and a stator and coil, which minimizes reluctance or stored magnetic energy. The direction of motion, force and magnetic field are aligned and are perpendicular to the air gap. When the air gap and corresponding stroke are moderate, large amounts of force and power can be delivered from a compact design. Several sizes of a new variable gap-reluctance linear motor design have been developed, characterized and applied. Practical application is demonstrated for linear resonance diaphragm refrigerant and gas compressors. A leaf spring suspension is used to dynamically match the motor to the resonance compressor load. Analysis and experimental results are combined to develop and characterize both the basic motor and integrated compressor designs.
{"title":"Variable Gap-Reluctance Linear Motor With Application to Linear Resonance Compressors","authors":"V. W. Popham, C. Lawrenson, R. F. Burr, B. Lipkens","doi":"10.1115/imece2001/nca-23518","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23518","url":null,"abstract":"\u0000 Variable gap-reluctance linear motors operate on the principle of electromagnetic attraction across an air gap between a moving armature and a stator and coil, which minimizes reluctance or stored magnetic energy. The direction of motion, force and magnetic field are aligned and are perpendicular to the air gap. When the air gap and corresponding stroke are moderate, large amounts of force and power can be delivered from a compact design. Several sizes of a new variable gap-reluctance linear motor design have been developed, characterized and applied. Practical application is demonstrated for linear resonance diaphragm refrigerant and gas compressors. A leaf spring suspension is used to dynamically match the motor to the resonance compressor load. Analysis and experimental results are combined to develop and characterize both the basic motor and integrated compressor designs.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122276490","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23528
Emily S. Heinze, M. Grissom, A. Belegundu
A general and practical approach is presented for optimizing structural additions to a base structure for broadband dynamic objectives when the base structure is excited by an arbitrary forcing function. The mode shapes and natural frequencies of the base structure are first found using a commercial finite element code or an experimental modal analysis. The mode shapes are used as basis shapes to reduce the size of the equations. The structural additions are then added as impedances into the reduced modal model. An efficient analysis algorithm is presented to reduce the computational burden for broadband analysis and optimization loops. The power transferred into a Broadband Vibration Absorber (BBVA) from a base structure is maximized as an example application. The numerical results are experimentally verified demonstrating the practical design capabilities of the method.
{"title":"Design and Optimization of Broadband Vibration Absorbers for Noise Control","authors":"Emily S. Heinze, M. Grissom, A. Belegundu","doi":"10.1115/imece2001/nca-23528","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23528","url":null,"abstract":"\u0000 A general and practical approach is presented for optimizing structural additions to a base structure for broadband dynamic objectives when the base structure is excited by an arbitrary forcing function. The mode shapes and natural frequencies of the base structure are first found using a commercial finite element code or an experimental modal analysis. The mode shapes are used as basis shapes to reduce the size of the equations. The structural additions are then added as impedances into the reduced modal model. An efficient analysis algorithm is presented to reduce the computational burden for broadband analysis and optimization loops. The power transferred into a Broadband Vibration Absorber (BBVA) from a base structure is maximized as an example application. The numerical results are experimentally verified demonstrating the practical design capabilities of the method.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133658751","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23507
A. Stokes, M. Conti, C. Corrado, Sevag H. Arzoumanian
We present a wave transmission line model developed to understand the transmission of energy through fluid-filled piping systems. The piping systems are represented as a sequence of components, e.g. valves, bends, and other components, connected with straight pipe sections. The transmission line model makes use of experimentally- or analytically-determined scattering coefficients to represent component behavior. The coefficients capture important coupling between fluid and structure, and among different structural wave types. The measurement of these coefficients is the subject of a separate paper [1]. The straight pipe segments are modeled analytically using fluid-filled, thick shell theory. Their motion is described in terms of amplitudes of freely traveling, left-and-right propagating waves. Results are presented which compare transfer functions measured on a piping system to predictions from the transmission line model, where each component is modeled with experimentally determined scattering coefficients. Initial results highlight important issues regarding the use of reciprocity, passivity, and causality to improve the quality of coefficients which are difficult to measure (for example, where certain frequency bands had high signal to noise). Algorithms for determining whether measured coefficients meet constraints on passivity, reciprocity, and causality are introduced. Predictions comparing analytical and measured coefficients are shown for a single-component (elbow) piping system.
{"title":"A Transmission Line Approach to the Acoustic Analysis of Piping Systems","authors":"A. Stokes, M. Conti, C. Corrado, Sevag H. Arzoumanian","doi":"10.1115/imece2001/nca-23507","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23507","url":null,"abstract":"\u0000 We present a wave transmission line model developed to understand the transmission of energy through fluid-filled piping systems. The piping systems are represented as a sequence of components, e.g. valves, bends, and other components, connected with straight pipe sections. The transmission line model makes use of experimentally- or analytically-determined scattering coefficients to represent component behavior. The coefficients capture important coupling between fluid and structure, and among different structural wave types. The measurement of these coefficients is the subject of a separate paper [1]. The straight pipe segments are modeled analytically using fluid-filled, thick shell theory. Their motion is described in terms of amplitudes of freely traveling, left-and-right propagating waves.\u0000 Results are presented which compare transfer functions measured on a piping system to predictions from the transmission line model, where each component is modeled with experimentally determined scattering coefficients. Initial results highlight important issues regarding the use of reciprocity, passivity, and causality to improve the quality of coefficients which are difficult to measure (for example, where certain frequency bands had high signal to noise). Algorithms for determining whether measured coefficients meet constraints on passivity, reciprocity, and causality are introduced. Predictions comparing analytical and measured coefficients are shown for a single-component (elbow) piping system.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131335503","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23510
Jae-Hak Woo, Xiandi Zeng
In the test-based SEA models, the major parameters are measured or estimated from measured quantities. One of the parameters is Damping Loss Factor (DLF) of the air (passenger) cavity of a vehicle. In the SEA model, the air cavity is divided into several sub-cavities. The required DLF for each sub-cavity can be calculated from the reverberation time (T60) measured in that sub-cavity in the vehicle. However, if nothing is done to separate one sub-cavity from other sub-cavities in the T60 measurement in the vehicle, the measured T60 for that sub-cavity is the T60 of the whole air cavity. When the resulted DLF is used in SEA model of that sub-cavity, it is the DLF of the whole air cavity that is used for a sub-cavity, which will result in an over/under-damped. Thus, the prediction from such a SEA model will have bias error especially in the higher frequency range. This has been seen in the results of a vehicle SEA model. In this paper, a method is proposed to estimate the DLF of each sub-cavity based on the T60 of the whole air cavity. When these estimated DLF’s are used in the SEA model for each sub-cavity, the correlation in SEA model was improved by 2.5∼3 dB above 1kHz.
{"title":"Damping Loss Factor Estimation for Test-Based Vehicle SEA Modeling","authors":"Jae-Hak Woo, Xiandi Zeng","doi":"10.1115/imece2001/nca-23510","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23510","url":null,"abstract":"In the test-based SEA models, the major parameters are measured or estimated from measured quantities. One of the parameters is Damping Loss Factor (DLF) of the air (passenger) cavity of a vehicle. In the SEA model, the air cavity is divided into several sub-cavities. The required DLF for each sub-cavity can be calculated from the reverberation time (T60) measured in that sub-cavity in the vehicle. However, if nothing is done to separate one sub-cavity from other sub-cavities in the T60 measurement in the vehicle, the measured T60 for that sub-cavity is the T60 of the whole air cavity. When the resulted DLF is used in SEA model of that sub-cavity, it is the DLF of the whole air cavity that is used for a sub-cavity, which will result in an over/under-damped. Thus, the prediction from such a SEA model will have bias error especially in the higher frequency range. This has been seen in the results of a vehicle SEA model. In this paper, a method is proposed to estimate the DLF of each sub-cavity based on the T60 of the whole air cavity. When these estimated DLF’s are used in the SEA model for each sub-cavity, the correlation in SEA model was improved by 2.5∼3 dB above 1kHz.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127416864","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23522
A. Davis, R. Nagem
We consider the diffraction of a time-harmonic acoustic plane wave by a rigid half-plane in a viscous fluid medium. The linearized equations of viscous fluid flow and the no-slip condition on the half-plane are used to derive a pair of disjoint Wiener-Hopf equations for the fluid stresses and velocities. The Wiener-Hopf equations are solved in conjunction with a requirement that the stresses are integrable near the edge of the half-plane. Specific wave components of the scattered velocity field are given explicitly, and the complete scattered velocity field is given in a form that is suitable for numerical computation.
{"title":"Acoustic Diffraction by a Half-Plane in a Viscous Fluid Medium","authors":"A. Davis, R. Nagem","doi":"10.1115/imece2001/nca-23522","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23522","url":null,"abstract":"\u0000 We consider the diffraction of a time-harmonic acoustic plane wave by a rigid half-plane in a viscous fluid medium. The linearized equations of viscous fluid flow and the no-slip condition on the half-plane are used to derive a pair of disjoint Wiener-Hopf equations for the fluid stresses and velocities. The Wiener-Hopf equations are solved in conjunction with a requirement that the stresses are integrable near the edge of the half-plane. Specific wave components of the scattered velocity field are given explicitly, and the complete scattered velocity field is given in a form that is suitable for numerical computation.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115292704","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23509
Yung-Chang Tan, Soo-Yeol Lee, M. Castanier, C. Pierre
A case study on the efficient prediction of vibration and power flow in a vehicle structure is presented. The modeling and analysis technique is based on component mode synthesis (CMS). First, the finite element model (FEM) of the entire vehicle structure is partitioned into component models. Then, the Craig-Bampton method is used to assemble a CMS model of the vehicle. The CMS matrices are further reduced by finding characteristic constraint (CC) modes. A relatively small number of CC modes are selected to capture the primary motion of the interface between components, yielding a highly reduced order model of the vehicle vibration in the low- to mid-frequency range. Using this reduced order model (ROM), the power flow and vibration response of the vehicle is analyzed for several design configurations. A design change in one component structure requires a re-analysis of the FEM for that component only, in order to generate a new ROM of the entire vehicle. It is found that this component-based approach allows efficient evaluation of the effectiveness of the vehicle design changes.
{"title":"Efficient Component-Based Vibration and Power Flow Analysis of a Vehicle Structure","authors":"Yung-Chang Tan, Soo-Yeol Lee, M. Castanier, C. Pierre","doi":"10.1115/imece2001/nca-23509","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23509","url":null,"abstract":"\u0000 A case study on the efficient prediction of vibration and power flow in a vehicle structure is presented. The modeling and analysis technique is based on component mode synthesis (CMS). First, the finite element model (FEM) of the entire vehicle structure is partitioned into component models. Then, the Craig-Bampton method is used to assemble a CMS model of the vehicle. The CMS matrices are further reduced by finding characteristic constraint (CC) modes. A relatively small number of CC modes are selected to capture the primary motion of the interface between components, yielding a highly reduced order model of the vehicle vibration in the low- to mid-frequency range. Using this reduced order model (ROM), the power flow and vibration response of the vehicle is analyzed for several design configurations. A design change in one component structure requires a re-analysis of the FEM for that component only, in order to generate a new ROM of the entire vehicle. It is found that this component-based approach allows efficient evaluation of the effectiveness of the vehicle design changes.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114689012","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 : 2001-11-11DOI: 10.1115/imece2001/nca-23535
Manjit S. Bajwa, Sean F. Wu
The HELS method (Wu, 2000) is extended to reconstruction of transient acoustic radiation from an impulsively accelerated object. The temporal acoustic pressure field is reconstructed by taking an inverse Fourier transformation of the acoustic pressure in the frequency domain. The infinite integral is replaced by a contour integral and evaluated using the residue theory. The formulations thus derived are valid for a spherical surface with an arbitrary normal velocity distribution. These formulations are used to reconstruct the normal surface velocities and transient acoustic fields generated by explosively expanding sphere, impulsively accelerating sphere, and impulsively accelerating baffled sphere. Results show that satisfactory reconstruction can be obtained with relatively few measurements taken around the object under consideration.
{"title":"Reconstruction of Transient Acoustic Radiation From Impulsively Accelerated Objects","authors":"Manjit S. Bajwa, Sean F. Wu","doi":"10.1115/imece2001/nca-23535","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23535","url":null,"abstract":"\u0000 The HELS method (Wu, 2000) is extended to reconstruction of transient acoustic radiation from an impulsively accelerated object. The temporal acoustic pressure field is reconstructed by taking an inverse Fourier transformation of the acoustic pressure in the frequency domain. The infinite integral is replaced by a contour integral and evaluated using the residue theory. The formulations thus derived are valid for a spherical surface with an arbitrary normal velocity distribution. These formulations are used to reconstruct the normal surface velocities and transient acoustic fields generated by explosively expanding sphere, impulsively accelerating sphere, and impulsively accelerating baffled sphere. Results show that satisfactory reconstruction can be obtained with relatively few measurements taken around the object under consideration.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116887521","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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