Pub Date : 2001-11-11DOI: 10.1115/imece2001/nca-23519
J. Corey
The simplicity of thermoacoustic engines promises power at low cost and high reliability, but demands a second output conversion, from acoustic to more useful form. Electric output is the most highly prized form. At CFIC, and now Q drive, we have been experimenting with our resonant linear alternators as active dynamic components in thermoacoustic machines, providing this conversion. This paper presents the reasons for considering such a system, implications on design, and the results of CFIC’s prototype testing so far.
{"title":"Recent Developments in Thermoacoustic Engine-Generators","authors":"J. Corey","doi":"10.1115/imece2001/nca-23519","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23519","url":null,"abstract":"\u0000 The simplicity of thermoacoustic engines promises power at low cost and high reliability, but demands a second output conversion, from acoustic to more useful form. Electric output is the most highly prized form. At CFIC, and now Q drive, we have been experimenting with our resonant linear alternators as active dynamic components in thermoacoustic machines, providing this conversion. This paper presents the reasons for considering such a system, implications on design, and the results of CFIC’s prototype testing so far.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"56 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130587621","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-23541
A. D. Danak, M. Hastings
A mathematical model is developed to examine the ability of American shad to detect ultrasound. The preliminary model is integral in obtaining a thorough understanding of the impact of the swimbladder and unique structures in the inner ear of the American shad on auditory sensitivity. Behavioral studies have already shown that a few fish species, including American shad (Alosa sapidissima) can detect ultrasonic frequencies up to 200 kHz (Dunning et.al., 1992; Nestler, Ploskey, and Pickery, 1992; Mann, Lu, and Popper, 1997; Mann, et. al 1998; Popper et.al, 1999). Although the auditory mechanisms involved are yet to be determined, all evidence obtained from this initial model suggests that the inner ear and auditory processing system play a key role. Once fully completed, such a model can be used to initiate development of a man-made sensor with similar capabilities of the shad ear for use in vivo clinical procedures using ultrasound.
建立了一个数学模型来检验美国鲱鱼检测超声波的能力。该初步模型对于全面了解美洲鲥鱼的鳔和内耳独特结构对听觉敏感性的影响是不可或缺的。行为研究已经表明，一些鱼类，包括美洲鲥鱼(Alosa sapidissima)可以探测到高达200千赫的超声波频率(Dunning等)。, 1992;Nestler, Ploskey, and Pickery, 1992;Mann, Lu, and Popper, 1997;Mann等人1998;Popper et.al, 1999)。虽然所涉及的听觉机制尚未确定，但从这个初始模型中获得的所有证据表明，内耳和听觉处理系统起着关键作用。一旦完全完成，这样的模型可以用于开发具有类似能力的人造传感器，用于使用超声波的体内临床程序。
{"title":"Analysis of a Biological Ultrasonic Sensory System","authors":"A. D. Danak, M. Hastings","doi":"10.1115/imece2001/nca-23541","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23541","url":null,"abstract":"\u0000 A mathematical model is developed to examine the ability of American shad to detect ultrasound. The preliminary model is integral in obtaining a thorough understanding of the impact of the swimbladder and unique structures in the inner ear of the American shad on auditory sensitivity. Behavioral studies have already shown that a few fish species, including American shad (Alosa sapidissima) can detect ultrasonic frequencies up to 200 kHz (Dunning et.al., 1992; Nestler, Ploskey, and Pickery, 1992; Mann, Lu, and Popper, 1997; Mann, et. al 1998; Popper et.al, 1999). Although the auditory mechanisms involved are yet to be determined, all evidence obtained from this initial model suggests that the inner ear and auditory processing system play a key role. Once fully completed, such a model can be used to initiate development of a man-made sensor with similar capabilities of the shad ear for use in vivo clinical procedures using ultrasound.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130044437","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-23537
K. Farinholt, D. Leo
This paper presents an investigation into control of sealed conical bores. Beginning with an impedance model of the enclosure, frequency domain and state-space models of the system are developed as functions of the geometric and mechanical properties of the cone. A discussion of coupling this acoustic model with the electrical and mechanical dynamics of a permanent magnet speaker are also presented. Using a sample geometry, the accuracy of this coupled model is validated against experimental results, indicating accuracy levels of 1.75% or lower in prediction of resonance frequencies. This paper concludes with a study on applying Linear Quadratic Regulator techniques to this system, relating trade-offs between average pressure and control voltages. The results of our simulations indicate that pressure reductions of 40.5% are attainable with average control voltages of 3.26 volts when subject to low level impulse disturbances, as applied to an example geometry.
{"title":"Active Acoustic Control of Conical Bores Through Actuating Boundary Conditions","authors":"K. Farinholt, D. Leo","doi":"10.1115/imece2001/nca-23537","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23537","url":null,"abstract":"\u0000 This paper presents an investigation into control of sealed conical bores. Beginning with an impedance model of the enclosure, frequency domain and state-space models of the system are developed as functions of the geometric and mechanical properties of the cone. A discussion of coupling this acoustic model with the electrical and mechanical dynamics of a permanent magnet speaker are also presented. Using a sample geometry, the accuracy of this coupled model is validated against experimental results, indicating accuracy levels of 1.75% or lower in prediction of resonance frequencies. This paper concludes with a study on applying Linear Quadratic Regulator techniques to this system, relating trade-offs between average pressure and control voltages. The results of our simulations indicate that pressure reductions of 40.5% are attainable with average control voltages of 3.26 volts when subject to low level impulse disturbances, as applied to an example geometry.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126178948","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-23504
S. Hambric, A. Yocum, T. Cawley, S. Willits
A new pump test facility has been designed and built at the Applied Research Laboratory at Penn State University (ARL/PSU). The loop, which complements the many other hydroacoustic measurement facilities at ARL/PSU, can accommodate a wide range of inflow piping, operating conditions, and pump configurations and has been constructed of high quality components to ensure its longevity as a world-class test facility. Measurements of pump hydrodynamic and hydroacoustic performance, as well as measurements of the characteristics of the turbulent flow entering pumps and other devices may be made in the facility. Measurements of the hydroacoustic character of passive devices, such as control valves, are also possible in the loop. The pump loop has been designed to minimize background noise contamination of vibration and fluid acoustic pressure measurements. Loop background noise levels measured with various sources in the building operating (compressors, motors, and other machinery) are extremely low and show that the noise control measures are effective. Wide optical access for Laser Doppler Velocimetry (LDV) measurements allows for measuring space-time correlations of pipe flow turbulence. Sample measurements of turbulence spectra and space-time correlations downstream of a 90 degree elbow are shown, and are of excellent quality.
{"title":"ARL/PENN State Pump Test Loop","authors":"S. Hambric, A. Yocum, T. Cawley, S. Willits","doi":"10.1115/imece2001/nca-23504","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23504","url":null,"abstract":"\u0000 A new pump test facility has been designed and built at the Applied Research Laboratory at Penn State University (ARL/PSU). The loop, which complements the many other hydroacoustic measurement facilities at ARL/PSU, can accommodate a wide range of inflow piping, operating conditions, and pump configurations and has been constructed of high quality components to ensure its longevity as a world-class test facility. Measurements of pump hydrodynamic and hydroacoustic performance, as well as measurements of the characteristics of the turbulent flow entering pumps and other devices may be made in the facility. Measurements of the hydroacoustic character of passive devices, such as control valves, are also possible in the loop. The pump loop has been designed to minimize background noise contamination of vibration and fluid acoustic pressure measurements. Loop background noise levels measured with various sources in the building operating (compressors, motors, and other machinery) are extremely low and show that the noise control measures are effective. Wide optical access for Laser Doppler Velocimetry (LDV) measurements allows for measuring space-time correlations of pipe flow turbulence. Sample measurements of turbulence spectra and space-time correlations downstream of a 90 degree elbow are shown, and are of excellent quality.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113965641","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-23529
S. Zheng, M. Zhuang
This paper presents a new optimization approach for the high-order finite difference schemes. Due to the fact that it is common for a sound field to consist of several dominant wavenumbers, the proposed numerical schemes are optimized at these dominant wavenumbers instead of over a range of wavenumber. These optimized multi-component schemes, as referred to in this paper, give very accurate solutions if used to predict an acoustic wave traveling with these dominant wavenumbers. In addition, for broadband waves, it is shown that the performance of the optimized upwind multi-component scheme is comparable to that of the optimized upwind broadband scheme, which is optimized over a range of wavenumber. The results of the Fourier analysis also show that the optimized central multi-component schemes are at least comparable to if not better than the optimized central broadband schemes when solving broadband waves.
{"title":"High-Order Optimized Numerical Schemes for Computational Aeroacoustics","authors":"S. Zheng, M. Zhuang","doi":"10.1115/imece2001/nca-23529","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23529","url":null,"abstract":"\u0000 This paper presents a new optimization approach for the high-order finite difference schemes. Due to the fact that it is common for a sound field to consist of several dominant wavenumbers, the proposed numerical schemes are optimized at these dominant wavenumbers instead of over a range of wavenumber. These optimized multi-component schemes, as referred to in this paper, give very accurate solutions if used to predict an acoustic wave traveling with these dominant wavenumbers. In addition, for broadband waves, it is shown that the performance of the optimized upwind multi-component scheme is comparable to that of the optimized upwind broadband scheme, which is optimized over a range of wavenumber. The results of the Fourier analysis also show that the optimized central multi-component schemes are at least comparable to if not better than the optimized central broadband schemes when solving broadband waves.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129452130","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-23532
L. Thompson, Limin Zhang, R. P. Ingel
Interpolation over frequency (wavenumber) bands with domain decomposition (substructure) methods is used to provide fast solutions to wave problems when large numbers of frequency evaluations are required. Dispersion analysis is used to quantify the accuracy of the frequency interpolation for both generalized Schur complement and regularized FETI-H substructuring methods. Wavenumber-frequency dispersion relations are compared with different numbers of condensed internal nodes, numbers of interpolation points, and frequency band size. Several numerical examples are performed which validate the conclusions made in the dispersion analysis.
{"title":"Domain Decomposition Methods With Frequency Band Interpolation for Computational Acoustics","authors":"L. Thompson, Limin Zhang, R. P. Ingel","doi":"10.1115/imece2001/nca-23532","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23532","url":null,"abstract":"\u0000 Interpolation over frequency (wavenumber) bands with domain decomposition (substructure) methods is used to provide fast solutions to wave problems when large numbers of frequency evaluations are required. Dispersion analysis is used to quantify the accuracy of the frequency interpolation for both generalized Schur complement and regularized FETI-H substructuring methods. Wavenumber-frequency dispersion relations are compared with different numbers of condensed internal nodes, numbers of interpolation points, and frequency band size. Several numerical examples are performed which validate the conclusions made in the dispersion analysis.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115152476","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}
An acoustic procedure is described for measuring the blade-frequency fluctuating forces developed by a powered model propeller operating behind a model of a ship’s hull or a wake generator in the anechoic test section of a wind tunnel. The sound pressure radiated by the propeller in a given direction is measured and its magnitude inserted into a simple theoretical relation to determine the alternating force developed by the propeller in that direction. Although the procedure was developed years ago, the details and limitations have not previously been described in the literature. Restrictions are discussed on the size of the propeller, location of the measurement point, measurement frequency, and the wind speed. Measurements determining the validity of the procedure are described, including comparisons of the magnitude of forces determined by this acoustic procedure with direct measurements made with a force dynamometer in a water tunnel.
{"title":"An Acoustic Procedure for Measuring Blade-Frequency Forces Generated by Model Ship Propellers","authors":"M. Strasberg","doi":"10.21236/ada410186","DOIUrl":"https://doi.org/10.21236/ada410186","url":null,"abstract":"\u0000 An acoustic procedure is described for measuring the blade-frequency fluctuating forces developed by a powered model propeller operating behind a model of a ship’s hull or a wake generator in the anechoic test section of a wind tunnel. The sound pressure radiated by the propeller in a given direction is measured and its magnitude inserted into a simple theoretical relation to determine the alternating force developed by the propeller in that direction. Although the procedure was developed years ago, the details and limitations have not previously been described in the literature. Restrictions are discussed on the size of the propeller, location of the measurement point, measurement frequency, and the wind speed. Measurements determining the validity of the procedure are described, including comparisons of the magnitude of forces determined by this acoustic procedure with direct measurements made with a force dynamometer in a water tunnel.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133262979","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-23516
K. Hong, S. Raveendra
Sound transmission and absorption of multi-layer sound absorbents are discussed in this manuscript. A new matrix formulation based on four pole parameters is utilized to derive the transmission loss and absorption coefficient of the absorbents. A transfer matrix relating pressure to acoustic velocity provides the required information to calculate the transmission loss and absorption coefficient. The multi-layer sound absorbents considered are structural panels, elastic porous linings and air-gaps. No limitations are imposed on the number of layers. Some realistic configurations of a multi-layer sound absorbent are studied to demonstrate the applicability of the four-pole parameter technique.
{"title":"Computation of Sound Transmission Loss and Absorption Coefficient of Multi-Layer Systems","authors":"K. Hong, S. Raveendra","doi":"10.1115/imece2001/nca-23516","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23516","url":null,"abstract":"\u0000 Sound transmission and absorption of multi-layer sound absorbents are discussed in this manuscript. A new matrix formulation based on four pole parameters is utilized to derive the transmission loss and absorption coefficient of the absorbents. A transfer matrix relating pressure to acoustic velocity provides the required information to calculate the transmission loss and absorption coefficient. The multi-layer sound absorbents considered are structural panels, elastic porous linings and air-gaps. No limitations are imposed on the number of layers. Some realistic configurations of a multi-layer sound absorbent are studied to demonstrate the applicability of the four-pole parameter technique.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128497412","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-23534
Amr A. Ali, O. Atassi, H. Atassi
The propagation of time-harmonic acoustic and vortical waves in a nonuniform swirling mean flow is studied. A second order accurate numerical scheme is used in solving the linearized Euler equations for an annular duct geometry. A three dimensional ‘exact’ nonreflecting boundary condition is applied downstream of the truncated duct. The numerical issues of implementing the nonreflecting boundary conditions are investigated. Solutions are presented for uniform and nonuniform swirling flows and compared with analytical solutions for validation. The computational results are in good agreement with the theory.
{"title":"Computation of Time Harmonic Acoustic Waves in a Duct With Nonuniform Mean Flow","authors":"Amr A. Ali, O. Atassi, H. Atassi","doi":"10.1115/imece2001/nca-23534","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23534","url":null,"abstract":"\u0000 The propagation of time-harmonic acoustic and vortical waves in a nonuniform swirling mean flow is studied. A second order accurate numerical scheme is used in solving the linearized Euler equations for an annular duct geometry. A three dimensional ‘exact’ nonreflecting boundary condition is applied downstream of the truncated duct. The numerical issues of implementing the nonreflecting boundary conditions are investigated. Solutions are presented for uniform and nonuniform swirling flows and compared with analytical solutions for validation. The computational results are in good agreement with the theory.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128564680","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-23511
Nam-Ho Kim, K. Choi, Jun Dong, C. Pierre, N. Vlahopoulos, Zheng-Dong Ma, M. Castanier
A design sensitivity analysis of a sequential structural-acoustic problem is presented. A frequency response analysis is used to obtain the dynamic behavior of an automotive structure, while the boundary element method is used to solve the pressure response of an interior, acoustic domain. For the purposes of design sensitivity analysis, a direct differentiation method and an adjoint variable method are presented. In the adjoint variable method, an adjoint load is obtained from the acoustic boundary element re-analysis, while the adjoint solution is calculated from the structural dynamic re-analysis. The evaluation of pressure sensitivity only involves a numerical integration process for the structural part. The proposed sensitivity results are compared to finite difference sensitivity results with excellent agreement.
{"title":"A Sequential Adjoint Variable Method in Design Sensitivity Analysis of NVH Problems","authors":"Nam-Ho Kim, K. Choi, Jun Dong, C. Pierre, N. Vlahopoulos, Zheng-Dong Ma, M. Castanier","doi":"10.1115/imece2001/nca-23511","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23511","url":null,"abstract":"\u0000 A design sensitivity analysis of a sequential structural-acoustic problem is presented. A frequency response analysis is used to obtain the dynamic behavior of an automotive structure, while the boundary element method is used to solve the pressure response of an interior, acoustic domain. For the purposes of design sensitivity analysis, a direct differentiation method and an adjoint variable method are presented. In the adjoint variable method, an adjoint load is obtained from the acoustic boundary element re-analysis, while the adjoint solution is calculated from the structural dynamic re-analysis. The evaluation of pressure sensitivity only involves a numerical integration process for the structural part. The proposed sensitivity results are compared to finite difference sensitivity results with excellent agreement.","PeriodicalId":387882,"journal":{"name":"Noise Control and Acoustics","volume":"9 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131753293","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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