Noise Control and Acoustics最新文献

{"title":"Experimental Investigations of an Electro-Dynamically Driven Thermoacoustic Cooler","authors":"L. Mongeau, A. Alexander, B. Minner, I. Paek, J. Braun","doi":"10.1115/imece2001/nca-23520","DOIUrl":"https://doi.org/10.1115/imece2001/nca-23520","url":null,"abstract":"\u0000 Experimental investigations of an electro-dynamically thermoacoustic cooler prototype were performed. The prototype was designed to provide 140 W of cooling across a 22 °C temperature lift. Operation using a 55% helium-argon mixture at a mean pressure of 20 bar and a frequency near 180 Hz was targeted. The prototype used a tuned “moving magnet” electro-mechanical actuator. Initial investigations aimed at characterizing the electro-mechanical behavior and performance of the driver. The acoustic response of the system with no cooling elements was then investigated to validate the experimental procedures. The thermal performance of the complete system was then measured over a range of operating conditions, for varying gas mixtures. Detailed sound pressure and temperature measurements provided information from which the overall efficiency, capacity, and temperature lift of the cooling system were estimated, in addition to the heat exchange coefficients and performance of the heat exchangers. Net acoustic power inputs of up to 120 W were achieved with an electro-acoustic transduction efficiency varying between 20% and 50%, reaching values as high as 60% in a few cases. In comparison, the theoretical maximum driver efficiency was 65%. The measured cooling capacity varied greatly and peaked near 130 W for a temperature lift of 12°C. The acoustic pressure amplitudes were near 3% of the mean pressure in the stack region, and the heat rejected to a secondary fluid reached 250 W. The best relative coefficient of performance achieved was less than 3% of Carnot, based on the net input acoustic power. The best overall efficiency achieved was thus 1.2% of Carnot. While the acoustic power level exceeded the target value for the desired cooling load, the cooling power was well below the expected value, and the target temperature lifts and efficiencies were not achieved. This was generally attributed to “nuisance” heat loads, acoustic streaming effects, and migration of species within the inhomogeneous mixture. The non-dimensional heat exchanger performance in the thermoacoustic system was found to be slightly less than that in a steady uniform flow when the root-mean-square particle velocity is used for a velocity scale, and the stack end temperature is used in the calculation of the temperature lift. It was also found that this performance value is significantly better than that predicted by linearized boundary layer models often used in linear acoustic models.","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":"122617687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"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":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":"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}

{"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":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":"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}

{"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":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":"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}

{"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":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":"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}

{"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":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":"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}

{"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":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":"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}

{"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":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":"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}

{"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":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":"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}

{"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":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":"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}