Journal of Computational Acoustics最新文献

{"title":"A Geometry Calibration Technique for Hydrophone Array with Sources in Near Field","authors":"Nan Zou, Yan Wang, Jin Fu, Guolong Liang","doi":"10.1142/S0218396X15400081","DOIUrl":"https://doi.org/10.1142/S0218396X15400081","url":null,"abstract":"A new algorithm involving flank array geometry calibration under strong multipath conditions is proposed to address the problem of installation errors and the shell deformation. The derived linear mapping relationship between geometric error of sensors and signal eigenvector reduces the calculating difficulty in near calibration mode. By regarding the reflection as coherent visual sources in known position, the compensation strategy of strong multipath matching is put forward. Cramer–Rao bound (CRB) analysis for the calibration mode is employed. Numerical simulations and lake trials verify the efficiency of the proposed algorithm and illustrate the performance improvement under strong multipath conditions.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1540008"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15400081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64075656","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":"Dolomitization Associated with Sea Level and Ocean Current Circulation in the Southern Marion Platform, Offshore Ne Australia","authors":"Tingting Zhang, Yuefeng Sun","doi":"10.1142/S0218396X15400056","DOIUrl":"https://doi.org/10.1142/S0218396X15400056","url":null,"abstract":"On the Southern Marion carbonate platform, dolomitization is triggered by the circulation of normal or slightly modified seawater and is related to changes in sedimentation rate and sea level change. Dolomitization further modifies formation permeability and fluid flow patterns. Dolostone/calcareous dolostone with large vuggy or moldic porosity is formed by fabric-preserving dissolution and recrystallization, which increases the pore space and facilitates the fluid flow effectively, with permeability ranging from 1mD to 10,000mD. The frame flexibility factor (γ) is a rock physics parameter which is a proxy of pore structure. We find that at given porosity dolostone with larger pores, higher permeability and higher sonic velocity usually has lower values of frame flexibility factor than limestone. After strong compaction and cementation, the limestone frame occludes fluid flow, prevents dolomitization and has permeability as low as 0.02mD. Acoustic impedance inversion confirms that the asymmetric geometry of the Southern Marion platform is shaped by the oceanographic currents, which are caused by the southward-flowing East Australian Current. Three layers of dolostone with large pores in the upper platform reveal strong fluid flow within the carbonate platform, leading to dolomitization and dissolution. These three strongly dolomitized zones follow the platform topography, indicating that the diagenetic fluid flow is driven by oceanographic currents. Three large-pore-formation dolomitization events match well with three highstands of sea level events, illustrating that the highstand of sea level induces the formation of dolomitization zones with large pores. This study demonstrates the positive feedback loop of dolomitization and ocean current circulation, as well as the relationship between dolomitization and sea level change, which could be applicable for better understanding subsurface fluid-rock interactions and dolomitization pore systems in other carbonate environments.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1540005"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15400056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64075742","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":"Molecular Dynamics Simulations of Sound Wave Propagation in a Gas and Thermo-Acoustic Effects on a Carbon Nanotube","authors":"Ayub, A. Zander, C. Howard, David M. Huang, B. Cazzolato","doi":"10.1142/S0218396X15400123","DOIUrl":"https://doi.org/10.1142/S0218396X15400123","url":null,"abstract":"Molecular dynamics (MD) simulations have been performed to study sound wave propagation in a simple monatomic gas (argon) and the thermo-acoustic effects on a single walled carbon nanotube (CNT). The objective of this study was to understand the acoustic behavior of CNTs in the presence of acoustic waves propagating in gaseous media. A plane sound wave was generated within a rectangular domain by oscillating a solid wall comprising Lennard-Jones (LJ) atoms with the same intermolecular potential as the gas molecules. A CNT was aligned parallel to the direction of the flow at the wall at the opposite end of the domain. Interatomic interactions in the CNT were modeled using the REBO potential. The behavior of the sound wave propagation in argon gas without the CNT was validated by comparison with a previous study. The simulation results show that the thermo-acoustic behavior of CNTs can be simulated accurately using MD and that large-scale MD can be performed in the ultrasonic frequency range. This investigation will contribute to an improved understanding of the acoustic absorption mechanism of these nanoscopic fibers.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1540012"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15400123","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076072","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":"Erratum: A Combined Doppler Scale Estimation Scheme for Underwater Acoustic OFDM System","authors":"Lu Ma, Gang Qiao, Songzuo Liu","doi":"10.1142/S0218396X16920016","DOIUrl":"https://doi.org/10.1142/S0218396X16920016","url":null,"abstract":"Since the performance of orthogonal frequency division multiplexing (OFDM) system is severely limited by frequency-dependent Doppler shifts over underwater acoustic (UWA) channels, a combined Doppler scale estimation scheme is proposed, containing two steps: (1) the initial Doppler scale estimation via transmitting two identical short OFDM symbols preceded by a cyclic prefix (CP) as a preamble prior to the data transmission; and (2) fine synchronization and Doppler scale estimation for each CP-OFDM block are achieved by the CP-based method, and eventually the resampling methodology is adopted for nonuniform Doppler shifts compensation. The proposed scheme has been tested with real data from the Songhua Lake experiment where the transmitter is moving at a speed of about 2.5 m/s, and the Yellow sea trial in which the transmitter and receiver are floating freely with waves and currents. Excellent performance results are obtained by block-by-block processing, without buffering the whole packet, which is suitable for real-time receiver processing over time-varying UWA channels.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"34 1","pages":"1540004"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X16920016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64078206","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":"Rock Physics Modeling of Unconsolidated Sands: Accounting for Partial Friction Grain Contacts and Heterogeneous Stress Field","authors":"Hui Li, De‐hua Han","doi":"10.1142/S0218396X15400019","DOIUrl":"https://doi.org/10.1142/S0218396X15400019","url":null,"abstract":"A partial friction heterogeneity model of a random-compacted granular pack can be formulated using two parameters (fp,f(μ)) to account for (1) macroscopic stress heterogeneity distribution of grain packs and (2) microscopic partial friction on the area of grain contact. This proposed partial friction heterogeneity model indicates that surface friction between grain contact is nonignorable, which results in tangential loading path being irreversible. Meanwhile, the tangential stress causes partial sliding on grain contact surface. Macroscopically, the effective shear modulus increases when either fraction of partial slip grain contacts or micro-friction on the area of grain contacts increases.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1540001"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15400019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64075474","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":"Sparse Spike Deconvolution of Seismic Data Using Trust-Region Based SQP Algorithm","authors":"Qingbao Zhou, Jinghuai Gao, Zhiguo Wang","doi":"10.1142/S0218396X15400020","DOIUrl":"https://doi.org/10.1142/S0218396X15400020","url":null,"abstract":"A new deconvolution algorithm for retrieving a sparse reflectivity series from noisy seismic traces is proposed. The problem is formulated as a constrained minimization, taking the approximation zero norm of reflectivity as the objective function. The resulting minimization is solved efficiently by the trust-region based sequential quadratic programming (SQP) method, which provides global convergence and local quadratic convergence rates under suitable assumptions. The null space decomposition method and the de-biasing method are employed to reduce computational complexity and further improve the calculation accuracy. Synthetic simulations indicate that the spikes on the reflectivity, both their positions and amplitudes, are recovered effectively by the proposed approach.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1540002"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15400020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64075564","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":"Time Frequency Wavenumber Analysis of Surface Waves and Signal Enhancement Using S-Transform","authors":"Zhao Zhang, Yuefeng Sun, K. Berteussen","doi":"10.1142/S0218396X1540010X","DOIUrl":"https://doi.org/10.1142/S0218396X1540010X","url":null,"abstract":"Highly dispersive surface waves resulting from the combination of strong lateral seafloor heterogeneities, shallow water depths and hard sea bottom severely degrade seismic reflection data quality. Considering that seismic signals are nonstationary and surface waves have various spectra over time, we proposed S-transform-based time frequency wavenumber analysis technique which allows the dynamic analysis of spectrum over time. The data is first transformed from the time-space domain to the time-wavenumber domain through one-dimensional Fourier transform over the spatial variable, then the variable-factor S-transform is applied over time. Nonstationary filtering is then designed to identify and separate surface waves in complex wavefields, based on its low frequency and low velocity properties, in the time-frequency-wavenumber (TFK) domain. Application to field data illustrates that with this technique, not only is the surface wave effectively suppressed, but also the reflective signals are enhanced, which confirm the validity of the method.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"23 1","pages":"1540010"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X1540010X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076438","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":"Pore Aspect Ratio Spectrum Inversion from Ultrasonic Measurements and Its Application","authors":"Fuyong Yan, De‐hua Han, Xue-Lian Chen","doi":"10.1142/S0218396X15400093","DOIUrl":"https://doi.org/10.1142/S0218396X15400093","url":null,"abstract":"We have conducted simultaneous ultrasonic velocity and pore volume change measurements on a carbonate rock sample. By including of pressure dependent porosity data, we have improved Cheng’s pore aspect ratio spectrum inversion methodology and made the inverted pore aspect ratio spectrum more realistic. Tang’s unified velocity dispersion and attenuation model is modified and extended to poroelastic media with complex pore structure under undrained condition. Using improved pore aspect ratio spectra inversion methodology and modified Tang’s model, we have explored the potential application of pore aspect ratio spectrum in prediction of seismic wave dispersion and attenuation.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"42 1","pages":"1540009"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S0218396X15400093","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64075775","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":"Efficient algorithm for long-range monostatic reverberation in shallow water using geometrical ray-bundle","authors":"Youngmin Choo, W. Seong, Keunhwa Lee","doi":"10.1142/S0218396X1550023X","DOIUrl":"https://doi.org/10.1142/S0218396X1550023X","url":null,"abstract":"An efficient algorithm for long-range monostatic reverberation is developed using geometrical ray-bundle as its propagation model. In the standard approach for reverberation modeling, scattered signals are numerically integrated along the rough surface. In this work, the integration along the rough surface is converted to an integration along the delay time of source signal. It can be expressed in an analytic form under the assumption of ignoring time-dispersion effect. Repetitive eigen-ray searches for calculating scattered signals are avoided by using a split-step marching algorithm for the range based on the geometrical ray-bundle. When the bottom is range-dependent, arrival times of scattered signals from the rough bottom at same range is different according to azimuthal angles and they cannot be directly summed in time domain. The reverberation signals along the azimuthal angles are interpolated to obtain new reverberation signals at certain times. They are summed to compute a time series reverberation signal from the rough sloping bottom. The algorithm is applied to problems of reverberation modeling workshop, and its results are compared with those from the standard reverberation algorithm.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"24 1","pages":"1650002"},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076744","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":"Low frequency bottom reverberation in a Pekeris waveguide with Lambert’s rule","authors":"M. Ainslie, D. Ellis, C. Harrison","doi":"10.1142/S0218396X15500228","DOIUrl":"https://doi.org/10.1142/S0218396X15500228","url":null,"abstract":"The requirement by modern navies to predict sonar performance in shallow water, whether for use in research, planning or operations, led to an initiative for the validation of reverberation models in the form of two Reverberation Modeling Workshops at the University of Texas at Austin in November 2006 and May 2008 [J. S. Perkins and E. I. Thorsos, Update on the reverberation modeling workshops, J. Acoust. Soc. Am. 126 (2009) 2208]. The problem considered here (Problem XI, from the 2006 workshop) requires the computation of reverberation versus time in a Pekeris waveguide with Lambert scattering from the seabed. Results from eigenray, normal mode and (hybrid) continuum methods are presented and compared for the time window 0.05s to 1000s after pulse transmission. Approximate analytical solutions are used to provide insight into the expected behavior of the reverberation and establish regimes of validity of numerical models. In situations where the regimes of validity of different methods coincide, the solutions of models applying these methods overlap. The overlapping solutions agree with each other within ±0.3dB. Their purpose is to provide a baseline against which future model improvements can be assessed and quantified.","PeriodicalId":54860,"journal":{"name":"Journal of Computational Acoustics","volume":"24 1","pages":"1650001"},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64076648","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}