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Three-dimensional acoustic wave equation modeling based on the optimal finite-difference scheme 被引量:4
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作者 蔡晓慧 刘洋 +4 位作者 任志明 王建民 陈志德 陈可洋 王成 《Applied Geophysics》 SCIE CSCD 2015年第3期409-420,469,共13页
Generally, FD coefficients can be obtained by using Taylor series expansion (TE) or optimization methods to minimize the dispersion error. However, the TE-based FD method only achieves high modeling precision over a... Generally, FD coefficients can be obtained by using Taylor series expansion (TE) or optimization methods to minimize the dispersion error. However, the TE-based FD method only achieves high modeling precision over a limited range of wavenumbers, and produces large numerical dispersion beyond this range. The optimal FD scheme based on least squares (LS) can guarantee high precision over a larger range of wavenumbers and obtain the best optimization solution at small computational cost. We extend the LS-based optimal FD scheme from two-dimensional (2D) forward modeling to three-dimensional (3D) and develop a 3D acoustic optimal FD method with high efficiency, wide range of high accuracy and adaptability to parallel computing. Dispersion analysis and forward modeling demonstrate that the developed FD method suppresses numerical dispersion. Finally, we use the developed FD method to source wavefield extrapolation and receiver wavefield extrapolation in 3D RTM. To decrease the computation time and storage requirements, the 3D RTM is implemented by combining the efficient boundary storage with checkpointing strategies on GPU. 3D RTM imaging results suggest that the 3D optimal FD method has higher precision than conventional methods. 展开更多
关键词 3D acoustic wave equation optimal finite-difference forward modeling reversetime migration
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3-D acoustic wave equation forward modeling with topography 被引量:6
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作者 Wang Xiangchun Liu Xuewei 《Applied Geophysics》 SCIE CSCD 2007年第1期8-15,共8页
In order to model the seismic wave field with surface topography, we present a method of transforming curved grids into rectangular grids in two different coordinate systems. Then the 3D wave equation in the transform... In order to model the seismic wave field with surface topography, we present a method of transforming curved grids into rectangular grids in two different coordinate systems. Then the 3D wave equation in the transformed coordinate system is derived. The wave field is modeled using the finite-difference method in the transformed coordinate system. The model calculation shows that this method is able to model the seismic wave field with fluctuating surface topography and achieve good results. Finally, the energy curves of the direct and reflected waves are analyzed to show that surface topography has a great influence on the seismic wave's dynamic properties. 展开更多
关键词 acoustic wave equation surface topography FINITE-DIFFERENCE numerical modeling.
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Suppress numerical dispersion in reversetime migration of acoustic wave equation using optimal nearly analytic discrete method
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作者 Liu Ming-Zhu He Bing-Shoug 《Applied Geophysics》 SCIE CSCD 2020年第1期133-142,170,共11页
Using staggered-grid finite difference method to solve seismic wave equation,large spatial grid and high dominant frequency of source cause numerical dispersion,staggeredgrid finite difference method,which can reduce ... Using staggered-grid finite difference method to solve seismic wave equation,large spatial grid and high dominant frequency of source cause numerical dispersion,staggeredgrid finite difference method,which can reduce the step spatial size and increase the order of difference,will multiply the calculation amount and reduce the efficiency of solving wave equation.The optimal nearly analytic discrete(ONAD)method can accurately solve the wave equation by using the combination of displacement and gradient of spatial nodes to approach the spatial partial derivative under rough grid and high-frequency condition.In this study,the ONAD method is introduced into the field of reverse-time migration(RTM)for performing forward-and reverse-time extrapolation of a two-dimensional acoustic equation,and the RTM based on ONAD method is realized via normalized cross-correlation imaging condition,effectively suppressed the numerical dispersion and improved the imaging accuracy.Using ONAD method to image the groove model and SEG/EAGE salt dome model by RTM,and comparing with the migration sections obtained by staggered-grid finite difference method with the same time order 2 nd and space order 4 th,results show that the RTM based on ONAD method can effectively suppress numerical dispersion caused by the high frequency components in source and shot records,and archive accurate imaging of complex geological structures especially the fine structure,and the migration sections of the measured data show that ONAD method has practical application value. 展开更多
关键词 acoustic wave equation RTM ONAD method numerical dispersion suppression
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A normalized wavefield separation cross-correlation imaging condition for reverse time migration based on Poynting vector 被引量:15
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作者 陈婷 何兵寿 《Applied Geophysics》 SCIE CSCD 2014年第2期158-166,253,共10页
Prestack reverse time migration(PSTM) is a common imaging method; however low-frequency noises reduce the structural imaging precision. Thus, the suppression of migration noises must be considered. The generation me... Prestack reverse time migration(PSTM) is a common imaging method; however low-frequency noises reduce the structural imaging precision. Thus, the suppression of migration noises must be considered. The generation mechanism of low-frequency noises is analyzed and the up-, down-, left-, and right-going waves are separated using the Poynting vector of the acoustic wave equation. The computational complexity and memory capacitance of the proposed method are far smaller than that required when using the conventional separation algorithm of 2D Fourier transform. The normalized wavefield separation crosscorrelation imaging condition is used to suppress low-frequency noises in reverse time migration and improve the imaging precision. Numerical experiments using the Marmousi model are performed and the results show that the up-, down-, left-, and right-going waves are well separated in the continuation of the wavefield using the Poynting vector. We compared the imaging results with the conventional method, Laplacian filtering, and wavefield separation with the 2D Fourier transform. The comparison shows that the migration noises are well suppressed using the normalized wavefield separation cross-correlation imaging condition and higher precision imaging results are obtained. 展开更多
关键词 acoustic wave equation Poynting vector wavefield separation normalized crosscorrelation migration noises
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Acoustic finite-difference modeling beyond conventional Courant-Friedrichs-Lewy stability limit:Approach based on variable-length temporal and spatial operators 被引量:2
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作者 Hongyu Zhou Yang Liu Jing Wang 《Earthquake Science》 2021年第2期123-136,共14页
Conventional finite-difference(FD)methods cannot model acoustic wave propagation beyond Courant-Friedrichs-Lewy(CFL)numbers 0.707 and 0.577 for two-dimensional(2D)and three-dimensional(3D)equal spacing cases,respectiv... Conventional finite-difference(FD)methods cannot model acoustic wave propagation beyond Courant-Friedrichs-Lewy(CFL)numbers 0.707 and 0.577 for two-dimensional(2D)and three-dimensional(3D)equal spacing cases,respectively,thereby limiting time step selection.Based on the definition of temporal and spatial FD operators,we propose a variable-length temporal and spatial operator strategy to model wave propagation beyond those CFL numbers while preserving accuracy.First,to simulate wave propagation beyond the conventional CFL stability limit,the lengths of the temporal operators are modified to exceed the lengths of the spatial operators for high-velocity zones.Second,to preserve the modeling accuracy,the velocity-dependent lengths of the temporal and spatial operators are adaptively varied.The maximum CFL numbers for the proposed method can reach 1.25 and 1.0 in high velocity contrast 2D and 3D simulation examples,respectively.We demonstrate the effectiveness of our method by modeling wave propagation in simple and complex media. 展开更多
关键词 acoustic wave equation FINITE-DIFFERENCE stability condition Courant-Friedrichs-Lewy numbers variable length.
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PREDICTION OF ACOUSTIC PERFORMANCE IN EXPANSION CHAMBER MUFFLERS WITH MEAN FLOW BY FINITE ELEMENT METHOD 被引量:4
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作者 Liu YadongLi CongxinRuan XueyuNational Die & Mold CAD EngineeringResearch Center,Shanghai Jiaotong University,Shanghai 200030, China 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2003年第3期292-295,304,共5页
The equation of wave propagation in a circular chamber with mean flow is obtained. Computational solution based on finite element method is employed to determine the transmission loss of expansive chamber. The effect ... The equation of wave propagation in a circular chamber with mean flow is obtained. Computational solution based on finite element method is employed to determine the transmission loss of expansive chamber. The effect of the mean flow and geometry (length of expansion chamber and expansion ratio)on acoustic attenuation performance is discussed, the predicted values of transmission loss of expansion chamber without and with mean flow are compared with those reported in the literature and they agree well. The accuracy of the prediction of transmission loss implies that finite element approximations are applicable to a lot of practical applications. 展开更多
关键词 wave equation Finite element method Exhaust mufflers acoustic characteristics
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Study of full waveform inversion based on L-BFGS algorithm
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作者 DENG Wubing HAN Liguo ZHANG Bo HUANG Fei HAN Miao 《Global Geology》 2012年第2期161-165,共5页
Full waveform inversion size of full waveform inversion will and the limitation of full waveform is mainly used to obtain high resolution velocity models of subsurface. The lead to a gigantic computation cost. Under t... Full waveform inversion size of full waveform inversion will and the limitation of full waveform is mainly used to obtain high resolution velocity models of subsurface. The lead to a gigantic computation cost. Under the available computer resource inversion, the authors propose L-BFGS algorithm as the optimization method to solve this problem. In order to demonstrate the flexibility of the method, three different numerical experi- ments have been done to analyze the properties of full waveform inversion based on L-BFGS. 展开更多
关键词 L-BFGS numerical optimization acoustic wave equation initial model full waveform inversion
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An imaging condition for reverse time migration based on wavefield decomposition
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作者 ZHAO Xu LIU Cai XU Cong 《Global Geology》 2015年第2期122-126,共5页
Reverse Time Migration(RTM) is a high precision imaging method of seismic wavefield at present,but low-frequency noises severely affect its imaging results.Thus one of most important aspect of RTM is to select the pro... Reverse Time Migration(RTM) is a high precision imaging method of seismic wavefield at present,but low-frequency noises severely affect its imaging results.Thus one of most important aspect of RTM is to select the proper noise suppression method.The wavefield characteristics of the Poynting vector are analyzed and the upgoing,downgoing,leftgoing and rightgoing waves are decomposed using the Poynting vector of the acoustic wave equation.The normalized wavefield decomposition cross-correlation imaging condition is used to suppress low-frequency noises in RTM and improve the imaging precision.Numerical experiments using the Mamousi velocity model are performed and the results demonstrate that the upgoing,downgoing,leftgoing and rightgoing waves are well decomposed using the Poynting vector.Compared with the normalized cross-correlation imaging and Laplacian filtering method,the results indicate that the low-frequency noises are well suppressed by using the normalized wavefield decomposition cross-correlation imaging condition. 展开更多
关键词 acoustic wave equation reverse time migration wavefield decomposition Poynting vector low- frequency noises
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STABILITY FOR IMPOSING ABSORBING BOUNDARY CONDITIONS IN THE FINITE ELEMENT SIMULATION OF ACOUSTIC WAVE PROPAGATION* 被引量:4
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作者 Wensheng Zhang Eric T. Chung Chaowei Wang 《Journal of Computational Mathematics》 SCIE CSCD 2014年第1期1-20,共20页
It is well-known that artificial boundary conditions are crucial for the efficient and accurate computations of wavefields on unbounded domains. In this paper, we investigate stability analysis for the wave equation c... It is well-known that artificial boundary conditions are crucial for the efficient and accurate computations of wavefields on unbounded domains. In this paper, we investigate stability analysis for the wave equation coupled with the first and the second order absorbing boundary conditions. The computational scheme is also developed. The approach allows the absorbing boundary conditions to be naturally imposed, which makes it easier for us to construct high order schemes for the absorbing boundary conditions. A thirdorder Lagrange finite element method with mass lumping is applied to obtain the spatial discretization of the wave equation. The resulting scheme is stable and is very efficient since no matrix inversion is needed at each time step. Moreover, we have shown both abstract and explicit conditional stability results for the fully-discrete schemes. The results are helpful for designing computational parameters in computations. Numerical computations are illustrated to show the efficiency and accuracy of our method. In particular, essentially no boundary reflection is seen at the artificial boundaries. 展开更多
关键词 STABILITY acoustic wave equation SIMULATION Finite element method Absorbing boundary conditions wave operator decomposition.
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A Weak Galerkin Mixed Finite Element Method for AcousticWave Equation
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作者 Xi Zhang Minfu Feng 《Advances in Applied Mathematics and Mechanics》 SCIE 2022年第4期936-959,共24页
This paper is concerned with the weak Galerkin mixed finite element method(WG-MFEM)for the second-order hyperbolic acoustic wave equation in velocity-pressure formulation.In this formulation,the original second-order ... This paper is concerned with the weak Galerkin mixed finite element method(WG-MFEM)for the second-order hyperbolic acoustic wave equation in velocity-pressure formulation.In this formulation,the original second-order differential equation in time and space is reduced to first-order differential equations by introducing the velocity and pressure variables.We employ the usual discontinuous piecewise-polynomials of degree k0 for the pressure and k+1 for the velocity.Furthermore,the normal component of the pressure on the interface of elements is enhanced by polynomials of degree k+1.The time derivative is approximated by the backward Euler difference.We show the stability of the semi-discrete and fullydiscrete schemes,and obtain the suboptimal order error estimates for the velocity and pressure variables.Numerical experiment confirms our theoretical analysis. 展开更多
关键词 acoustic wave equation velocity-pressure formulation WG-MFEM
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Efficient Simulation of Wave Propagation with Implicit Finite Difference Schemes 被引量:2
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作者 Wensheng Zhang Li Tong Eric T.Chung 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2012年第2期205-228,共24页
Finite difference method is an important methodology in the approximation of waves.In this paper,we will study two implicit finite difference schemes for the simulation of waves.They are the weighted alternating direc... Finite difference method is an important methodology in the approximation of waves.In this paper,we will study two implicit finite difference schemes for the simulation of waves.They are the weighted alternating direction implicit(ADI)scheme and the locally one-dimensional(LOD)scheme.The approximation errors,stability conditions,and dispersion relations for both schemes are investigated.Our analysis shows that the LOD implicit scheme has less dispersion error than that of the ADI scheme.Moreover,the unconditional stability for both schemes with arbitrary spatial accuracy is established for the first time.In order to improve computational efficiency,numerical algorithms based on message passing interface(MPI)are implemented.Numerical examples of wave propagation in a three-layer model and a standard complex model are presented.Our analysis and comparisons show that both ADI and LOD schemes are able to efficiently and accurately simulate wave propagation in complex media. 展开更多
关键词 acoustic wave equation implicit schemes ADI LOD stability condition dispersion curve MPI parallel computations
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High-Order Schemes Combining the Modified Equation Approach and Discontinuous Galerkin Approximations for the Wave Equation
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作者 Cyril Agut Julien Diaz Abdelaaziz Ezziani 《Communications in Computational Physics》 SCIE 2012年第2期691-708,共18页
We present a new high ordermethod in space and time for solving the wave equation,based on a newinterpretation of the“Modified Equation”technique.Indeed,contrary to most of the works,we consider the time discretizat... We present a new high ordermethod in space and time for solving the wave equation,based on a newinterpretation of the“Modified Equation”technique.Indeed,contrary to most of the works,we consider the time discretization before the space discretization.After the time discretization,an additional biharmonic operator appears,which can not be discretized by classical finite elements.We propose a new Discontinuous Galerkinmethod for the discretization of this operator,andwe provide numerical experiments proving that the new method is more accurate than the classicalModified Equation technique with a lower computational burden. 展开更多
关键词 High order schemes discontinuous Galerkin method acoustic wave equation
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