The Experts below are selected from a list of 92277 Experts worldwide ranked by ideXlab platform

Qing Huo Liu - One of the best experts on this subject based on the ideXlab platform.

  • Domain decomposition based on the spectral element method for frequency Domain computational elastodynamics
    Science China-earth Sciences, 2021
    Co-Authors: Yuanguo Zhou, Linlin Shi, Na Liu, Mingwei Zhuang, Qing Huo Liu
    Abstract:

    We propose a Domain decomposition method based on the spectral element method (DDM-SEM) for elastic wave computation in frequency Domain. It combines the high accuracy of the spectral element method and the high degree of parallelism of a Domain decomposition technique, which makes this method suitable for accurate and efficient simulations of large scale problems in elastodynamics. In the DDM-SEM, the original large-scale problem is divided into a number of well designed subDomains. We use the spectral element method independently for each subDomain, and the neighboring subDomains are connected by a frequency-Domain Version of Riemann transmission condition (RTC) for elastic waves. For the proposed method, we can employ the non-conforming meshes and different interpolation orders in different subDomains to maximize the efficiency. By separating the internal and boundary unknowns of each subDomain, an efficient and naturally parallelizable block LDU direct solver is developed to solve the final system matrix. Numerical experiments verify its accuracy and efficiency, and show that the proposed DDM-SEM can be a promising numerical tool for accurately and effectively solving large and multi-scale problems of elastic waves. It is potentially valuable for the frequency Domain seismic inVersion where multiple source illuminations are required.

  • spectral element method and Domain decomposition for low frequency subsurface em simulation
    IEEE Geoscience and Remote Sensing Letters, 2016
    Co-Authors: Yuanguo Zhou, Linlin Shi, Na Liu, Chunhui Zhu, Hai Liu, Qing Huo Liu
    Abstract:

    Low-frequency subsurface electromagnetic measurements are important tools for characterizing natural resources and environmental wastes. Rapid simulations of low-frequency subsurface electromagnetic measurements are still a challenge because of the large computational Domain and low-frequency breakdown phenomenon. We develop an effective method to simulate these low-frequency subsurface electromagnetic measurements by using the spectral element method together with a Domain decomposition method (DDM). A specific mesh has been designed based on the traveling wave nature in the air and the diffusion field nature in the underground space to greatly reduce the number of unknowns. The frequency-Domain Version of the Riemann solver (upwind flux) is used as an effective transmission condition to simulate the interactions between neighboring subDomains in DDM. Several numerical examples demonstrate the efficiency of the proposed approach in low-frequency subsurface electromagnetics simulations.

  • spectral methods and Domain decomposition for nanophotonic applications
    Proceedings of the IEEE, 2013
    Co-Authors: Ma Luo, Yun Lin, Qing Huo Liu
    Abstract:

    Nanophotonic applications often involve large-scale problems with excessive demand on computational resources. We develop a Domain decomposition method (DDM) to reduce computer memory and central processing unit (CPU) time requirements by combining the spectral element method (SEM) and the spectral integral method (SIM) for large-scale finite periodic structures. The interior scattering subDomains within each period are modeled by the SEM while the exterior scattering problem is modeled by the SIM. The interactions between neighboring subDomains are modeled by the frequency-Domain Version of the Riemann solver. Numerical convergence of the Riemann solver is fast and weakly dependent on the size of the system. Two sets of examples demonstrate the typical nanophotonic applications: The first periodic system is a vertical coupling waveguide based on a photonic crystal slab which opens a way to construct and simulate optical circuits. The second periodic system is a finite-sized metamaterial with an effective negative refractive index, whose edge effects are visualized and analyzed.

P H Pathak - One of the best experts on this subject based on the ideXlab platform.

  • a time Domain formulation of the uniform geometrical theory of diffraction for scattering from a smooth convex surface
    IEEE Transactions on Antennas and Propagation, 2007
    Co-Authors: P R Rousseau, P H Pathak, Hsitseng Chou
    Abstract:

    A time-Domain Version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in closed form, the transient electromagnetic scattering from a smooth convex surface excited by a general time impulsive astigmatic ray field. This TD-UTD impulse response is obtained by employing an analytic time transform (ATT) for the inVersion in time of an available and accurate corresponding frequency Domain UTD (FD-UTD) solution. The ATT is employed because it overcomes the difficulties that occur when inverting FD-UTD fields associated with rays that traverse line or smooth caustics. Furthermore, the TD-UTD response to a general pulsed astigmatic wave excitation may be found by a convolution of the general excitation with the TD-UTD impulse response which can be performed in closed form. Some numerical examples illustrating the utility of this TD-UTD are presented.

  • time Domain uniform geometrical theory of diffraction for a curved wedge
    IEEE Transactions on Antennas and Propagation, 1995
    Co-Authors: P R Rousseau, P H Pathak
    Abstract:

    A time-Domain Version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in closed form, the transient electromagnetic scattering from a perfectly conducting, arbitrarily curved wedge excited by a general time impulsive astigmatic wavefront. This TD-UTD impulse response is obtained by a Fourier inVersion of the corresponding frequency Domain UTD solution. An analytic signal representation of the transient fields is used because it provides a very simple procedure to avoid the difficulties that result when inverting frequency Domain UTD fields associated with rays that traverse line or smooth caustics. The TD-UTD response to a more general transient wave excitation of the wedge may be found via convolution. A very useful representation for modeling a general pulsed astigmatic wave excitation is also developed which, in particular, allows its convolution with the TD-UTD impulse response to be done in closed form. Some numerical examples illustrating the utility of these developments are presented.

P R Rousseau - One of the best experts on this subject based on the ideXlab platform.

  • a time Domain formulation of the uniform geometrical theory of diffraction for scattering from a smooth convex surface
    IEEE Transactions on Antennas and Propagation, 2007
    Co-Authors: P R Rousseau, P H Pathak, Hsitseng Chou
    Abstract:

    A time-Domain Version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in closed form, the transient electromagnetic scattering from a smooth convex surface excited by a general time impulsive astigmatic ray field. This TD-UTD impulse response is obtained by employing an analytic time transform (ATT) for the inVersion in time of an available and accurate corresponding frequency Domain UTD (FD-UTD) solution. The ATT is employed because it overcomes the difficulties that occur when inverting FD-UTD fields associated with rays that traverse line or smooth caustics. Furthermore, the TD-UTD response to a general pulsed astigmatic wave excitation may be found by a convolution of the general excitation with the TD-UTD impulse response which can be performed in closed form. Some numerical examples illustrating the utility of this TD-UTD are presented.

  • time Domain uniform geometrical theory of diffraction for a curved wedge
    IEEE Transactions on Antennas and Propagation, 1995
    Co-Authors: P R Rousseau, P H Pathak
    Abstract:

    A time-Domain Version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in closed form, the transient electromagnetic scattering from a perfectly conducting, arbitrarily curved wedge excited by a general time impulsive astigmatic wavefront. This TD-UTD impulse response is obtained by a Fourier inVersion of the corresponding frequency Domain UTD solution. An analytic signal representation of the transient fields is used because it provides a very simple procedure to avoid the difficulties that result when inverting frequency Domain UTD fields associated with rays that traverse line or smooth caustics. The TD-UTD response to a more general transient wave excitation of the wedge may be found via convolution. A very useful representation for modeling a general pulsed astigmatic wave excitation is also developed which, in particular, allows its convolution with the TD-UTD impulse response to be done in closed form. Some numerical examples illustrating the utility of these developments are presented.

Linlin Shi - One of the best experts on this subject based on the ideXlab platform.

  • Domain decomposition based on the spectral element method for frequency Domain computational elastodynamics
    Science China-earth Sciences, 2021
    Co-Authors: Yuanguo Zhou, Linlin Shi, Na Liu, Mingwei Zhuang, Qing Huo Liu
    Abstract:

    We propose a Domain decomposition method based on the spectral element method (DDM-SEM) for elastic wave computation in frequency Domain. It combines the high accuracy of the spectral element method and the high degree of parallelism of a Domain decomposition technique, which makes this method suitable for accurate and efficient simulations of large scale problems in elastodynamics. In the DDM-SEM, the original large-scale problem is divided into a number of well designed subDomains. We use the spectral element method independently for each subDomain, and the neighboring subDomains are connected by a frequency-Domain Version of Riemann transmission condition (RTC) for elastic waves. For the proposed method, we can employ the non-conforming meshes and different interpolation orders in different subDomains to maximize the efficiency. By separating the internal and boundary unknowns of each subDomain, an efficient and naturally parallelizable block LDU direct solver is developed to solve the final system matrix. Numerical experiments verify its accuracy and efficiency, and show that the proposed DDM-SEM can be a promising numerical tool for accurately and effectively solving large and multi-scale problems of elastic waves. It is potentially valuable for the frequency Domain seismic inVersion where multiple source illuminations are required.

  • spectral element method and Domain decomposition for low frequency subsurface em simulation
    IEEE Geoscience and Remote Sensing Letters, 2016
    Co-Authors: Yuanguo Zhou, Linlin Shi, Na Liu, Chunhui Zhu, Hai Liu, Qing Huo Liu
    Abstract:

    Low-frequency subsurface electromagnetic measurements are important tools for characterizing natural resources and environmental wastes. Rapid simulations of low-frequency subsurface electromagnetic measurements are still a challenge because of the large computational Domain and low-frequency breakdown phenomenon. We develop an effective method to simulate these low-frequency subsurface electromagnetic measurements by using the spectral element method together with a Domain decomposition method (DDM). A specific mesh has been designed based on the traveling wave nature in the air and the diffusion field nature in the underground space to greatly reduce the number of unknowns. The frequency-Domain Version of the Riemann solver (upwind flux) is used as an effective transmission condition to simulate the interactions between neighboring subDomains in DDM. Several numerical examples demonstrate the efficiency of the proposed approach in low-frequency subsurface electromagnetics simulations.

Yuanguo Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Domain decomposition based on the spectral element method for frequency Domain computational elastodynamics
    Science China-earth Sciences, 2021
    Co-Authors: Yuanguo Zhou, Linlin Shi, Na Liu, Mingwei Zhuang, Qing Huo Liu
    Abstract:

    We propose a Domain decomposition method based on the spectral element method (DDM-SEM) for elastic wave computation in frequency Domain. It combines the high accuracy of the spectral element method and the high degree of parallelism of a Domain decomposition technique, which makes this method suitable for accurate and efficient simulations of large scale problems in elastodynamics. In the DDM-SEM, the original large-scale problem is divided into a number of well designed subDomains. We use the spectral element method independently for each subDomain, and the neighboring subDomains are connected by a frequency-Domain Version of Riemann transmission condition (RTC) for elastic waves. For the proposed method, we can employ the non-conforming meshes and different interpolation orders in different subDomains to maximize the efficiency. By separating the internal and boundary unknowns of each subDomain, an efficient and naturally parallelizable block LDU direct solver is developed to solve the final system matrix. Numerical experiments verify its accuracy and efficiency, and show that the proposed DDM-SEM can be a promising numerical tool for accurately and effectively solving large and multi-scale problems of elastic waves. It is potentially valuable for the frequency Domain seismic inVersion where multiple source illuminations are required.

  • spectral element method and Domain decomposition for low frequency subsurface em simulation
    IEEE Geoscience and Remote Sensing Letters, 2016
    Co-Authors: Yuanguo Zhou, Linlin Shi, Na Liu, Chunhui Zhu, Hai Liu, Qing Huo Liu
    Abstract:

    Low-frequency subsurface electromagnetic measurements are important tools for characterizing natural resources and environmental wastes. Rapid simulations of low-frequency subsurface electromagnetic measurements are still a challenge because of the large computational Domain and low-frequency breakdown phenomenon. We develop an effective method to simulate these low-frequency subsurface electromagnetic measurements by using the spectral element method together with a Domain decomposition method (DDM). A specific mesh has been designed based on the traveling wave nature in the air and the diffusion field nature in the underground space to greatly reduce the number of unknowns. The frequency-Domain Version of the Riemann solver (upwind flux) is used as an effective transmission condition to simulate the interactions between neighboring subDomains in DDM. Several numerical examples demonstrate the efficiency of the proposed approach in low-frequency subsurface electromagnetics simulations.