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Haibo Chen - One of the best experts on this subject based on the ideXlab platform.

  • free vibration analysis of elastic structures submerged in an infinite or semi infinite Fluid Domain by means of a coupled fe be solver
    Journal of Computational Physics, 2018
    Co-Authors: Changjun Zheng, Chuanzeng Zhang, Haifeng Gao, Haibo Chen
    Abstract:

    Abstract The vibration behavior of thin elastic structures can be noticeably influenced by the surrounding water, which represents a kind of heavy Fluid. Since the feedback of the acoustic pressure onto the structure cannot be neglected in this case, a strong coupled scheme between the structural and Fluid Domains is usually required. In this work, a coupled finite element and boundary element (FE–BE) solver is developed for the free vibration analysis of structures submerged in an infinite Fluid Domain or a semi-infinite Fluid Domain with a free water surface. The structure is modeled by the finite element method (FEM). The compressibility of the Fluid is taken into account, and hence the Helmholtz equation serves as the governing equation of the Fluid Domain. The boundary element method (BEM) is employed to model the Fluid Domain, and a boundary integral formulation with a half-space fundamental solution is used to satisfy the Dirichlet boundary condition on the free water surface exactly. The resulting nonlinear eigenvalue problem (NEVP) is converted into a small linear one by using a contour integral method. Adequate modifications are suggested to improve the efficiency of the contour integral method and avoid missing the eigenfrequencies of interest. The Burton–Miller method is used to filter out the fictitious eigenfrequencies of the boundary integral formulations. Numerical examples are given to demonstrate the accuracy and applicability of the developed eigensolver, and also show that the Fluid-loading effect strongly depends on both the water depth and the mode shapes.

  • coupled fe be method for eigenvalue analysis of elastic structures submerged in an infinite Fluid Domain
    International Journal for Numerical Methods in Engineering, 2017
    Co-Authors: Changjun Zheng, Chuanzeng Zhang, Haifeng Gao, Haibo Chen
    Abstract:

    Summary For thin elastic structures submerged in heavy Fluid, e.g., water, a strong interaction between the structural Domain and the Fluid Domain occurs and significantly alters the eigenfrequencies. Therefore, the eigenanalysis of the Fluid–structure interaction system is necessary. In this paper, a coupled finite element and boundary element (FE–BE) method is developed for the numerical eigenanalysis of the Fluid–structure interaction problems. The structure is modeled by the finite element method. The compressibility of the Fluid is taken into consideration, and hence the Helmholtz equation is employed as the governing equation and solved by the boundary element method (BEM). The resulting nonlinear eigenvalue problem is converted into a small linear one by applying a contour integral method. Adequate modifications are suggested to improve the efficiency of the contour integral method and avoid missing the eigenvalues of interest. The Burton–Miller formulation is applied to tackle the fictitious eigenfrequency problem of the BEM, and the optimal choice of its coupling parameter is investigated for the coupled FE–BE method. Numerical examples are given and discussed to demonstrate the effectiveness and accuracy of the developed FE–BE method. Copyright © 2016 John Wiley & Sons, Ltd.

Changjun Zheng - One of the best experts on this subject based on the ideXlab platform.

  • free vibration analysis of elastic structures submerged in an infinite or semi infinite Fluid Domain by means of a coupled fe be solver
    Journal of Computational Physics, 2018
    Co-Authors: Changjun Zheng, Chuanzeng Zhang, Haifeng Gao, Haibo Chen
    Abstract:

    Abstract The vibration behavior of thin elastic structures can be noticeably influenced by the surrounding water, which represents a kind of heavy Fluid. Since the feedback of the acoustic pressure onto the structure cannot be neglected in this case, a strong coupled scheme between the structural and Fluid Domains is usually required. In this work, a coupled finite element and boundary element (FE–BE) solver is developed for the free vibration analysis of structures submerged in an infinite Fluid Domain or a semi-infinite Fluid Domain with a free water surface. The structure is modeled by the finite element method (FEM). The compressibility of the Fluid is taken into account, and hence the Helmholtz equation serves as the governing equation of the Fluid Domain. The boundary element method (BEM) is employed to model the Fluid Domain, and a boundary integral formulation with a half-space fundamental solution is used to satisfy the Dirichlet boundary condition on the free water surface exactly. The resulting nonlinear eigenvalue problem (NEVP) is converted into a small linear one by using a contour integral method. Adequate modifications are suggested to improve the efficiency of the contour integral method and avoid missing the eigenfrequencies of interest. The Burton–Miller method is used to filter out the fictitious eigenfrequencies of the boundary integral formulations. Numerical examples are given to demonstrate the accuracy and applicability of the developed eigensolver, and also show that the Fluid-loading effect strongly depends on both the water depth and the mode shapes.

  • coupled fe be method for eigenvalue analysis of elastic structures submerged in an infinite Fluid Domain
    International Journal for Numerical Methods in Engineering, 2017
    Co-Authors: Changjun Zheng, Chuanzeng Zhang, Haifeng Gao, Haibo Chen
    Abstract:

    Summary For thin elastic structures submerged in heavy Fluid, e.g., water, a strong interaction between the structural Domain and the Fluid Domain occurs and significantly alters the eigenfrequencies. Therefore, the eigenanalysis of the Fluid–structure interaction system is necessary. In this paper, a coupled finite element and boundary element (FE–BE) method is developed for the numerical eigenanalysis of the Fluid–structure interaction problems. The structure is modeled by the finite element method. The compressibility of the Fluid is taken into consideration, and hence the Helmholtz equation is employed as the governing equation and solved by the boundary element method (BEM). The resulting nonlinear eigenvalue problem is converted into a small linear one by applying a contour integral method. Adequate modifications are suggested to improve the efficiency of the contour integral method and avoid missing the eigenvalues of interest. The Burton–Miller formulation is applied to tackle the fictitious eigenfrequency problem of the BEM, and the optimal choice of its coupling parameter is investigated for the coupled FE–BE method. Numerical examples are given and discussed to demonstrate the effectiveness and accuracy of the developed FE–BE method. Copyright © 2016 John Wiley & Sons, Ltd.

Paul A Milewski - One of the best experts on this subject based on the ideXlab platform.

  • dynamics of gravity capillary solitary waves in deep water
    Journal of Fluid Mechanics, 2012
    Co-Authors: Zhan Wang, Paul A Milewski
    Abstract:

    The dynamics of solitary gravity–capillary water waves propagating on the surface of a three-dimensional Fluid Domain is studied numerically. In order to accurately compute complex time-dependent solutions, we simplify the full potential flow problem by using surface variables and taking a particular cubic truncation possessing a Hamiltonian with desirable properties. This approximation agrees remarkably well with the full equations for the bifurcation curves, wave profiles and the dynamics of solitary waves for a two-dimensional Fluid Domain, and with higher-order truncations in three dimensions. Fully localized solitary waves are then computed in the three-dimensional problem and the stability and interaction of both line and localized solitary waves are investigated via numerical time integration of the equations. There are many solitary wave branches, indexed by their finite energy as their amplitude tends to zero. The dynamics of the solitary waves is complex, involving nonlinear focusing of wavepackets, quasi-elastic collisions, and the generation of propagating, spatially localized, time-periodic structures akin to breathers.

  • dynamics of gravity capillary solitary waves in deep water
    arXiv: Fluid Dynamics, 2012
    Co-Authors: Zhan Wang, Paul A Milewski
    Abstract:

    The dynamics of solitary gravity-capillary water waves propagating on the surface of a three-dimensional Fluid Domain is studied numerically. In order to accurately compute complex time dependent solutions, we simplify the full potential flow problem by taking a cubic truncation of the scaled Dirichlet-to-Neumann operator for the normal velocity on the free surface. This approximation agrees remarkably well with the full equations for the bifurcation curves, wave profiles and the dynamics of solitary waves for a two-dimensional Fluid Domain. Fully localised solitary waves are then computed in the three-dimensional problem and the stability and interaction of both line and localized solitary waves are investigated via numerical time integration of the equations. The solitary wave branches are indexed by their finite energy at small amplitude, and the dynamics of the solitary waves is complex involving nonlinear focussing of wave packets, quasi-elastic collisions, and the generation of propagating, spatially localised, time-periodic structures (breathers).

Sriman Kumar Bhattacharyya - One of the best experts on this subject based on the ideXlab platform.

  • time Domain analysis of infinite reservoir by finite element method using a novel far boundary condition
    Finite Elements in Analysis and Design, 1999
    Co-Authors: Damodar Maity, Sriman Kumar Bhattacharyya
    Abstract:

    Abstract The focus of the present paper is on the time-Domain analysis of a dam–reservoir system using a novel far-boundary condition to model an infinite Fluid Domain to a finite one. The method is based on the finite element discretization of the complete system assuming only pressure to be the nodal unknown parameter and the Fluid to be compressible. The truncation boundary condition is derived numerically from the classical wave equation. Studies show the accuracy of the proposed far-boundary condition, using finite element method, while comparing with the existing ones available in the literature.

Haifeng Gao - One of the best experts on this subject based on the ideXlab platform.

  • free vibration analysis of elastic structures submerged in an infinite or semi infinite Fluid Domain by means of a coupled fe be solver
    Journal of Computational Physics, 2018
    Co-Authors: Changjun Zheng, Chuanzeng Zhang, Haifeng Gao, Haibo Chen
    Abstract:

    Abstract The vibration behavior of thin elastic structures can be noticeably influenced by the surrounding water, which represents a kind of heavy Fluid. Since the feedback of the acoustic pressure onto the structure cannot be neglected in this case, a strong coupled scheme between the structural and Fluid Domains is usually required. In this work, a coupled finite element and boundary element (FE–BE) solver is developed for the free vibration analysis of structures submerged in an infinite Fluid Domain or a semi-infinite Fluid Domain with a free water surface. The structure is modeled by the finite element method (FEM). The compressibility of the Fluid is taken into account, and hence the Helmholtz equation serves as the governing equation of the Fluid Domain. The boundary element method (BEM) is employed to model the Fluid Domain, and a boundary integral formulation with a half-space fundamental solution is used to satisfy the Dirichlet boundary condition on the free water surface exactly. The resulting nonlinear eigenvalue problem (NEVP) is converted into a small linear one by using a contour integral method. Adequate modifications are suggested to improve the efficiency of the contour integral method and avoid missing the eigenfrequencies of interest. The Burton–Miller method is used to filter out the fictitious eigenfrequencies of the boundary integral formulations. Numerical examples are given to demonstrate the accuracy and applicability of the developed eigensolver, and also show that the Fluid-loading effect strongly depends on both the water depth and the mode shapes.

  • coupled fe be method for eigenvalue analysis of elastic structures submerged in an infinite Fluid Domain
    International Journal for Numerical Methods in Engineering, 2017
    Co-Authors: Changjun Zheng, Chuanzeng Zhang, Haifeng Gao, Haibo Chen
    Abstract:

    Summary For thin elastic structures submerged in heavy Fluid, e.g., water, a strong interaction between the structural Domain and the Fluid Domain occurs and significantly alters the eigenfrequencies. Therefore, the eigenanalysis of the Fluid–structure interaction system is necessary. In this paper, a coupled finite element and boundary element (FE–BE) method is developed for the numerical eigenanalysis of the Fluid–structure interaction problems. The structure is modeled by the finite element method. The compressibility of the Fluid is taken into consideration, and hence the Helmholtz equation is employed as the governing equation and solved by the boundary element method (BEM). The resulting nonlinear eigenvalue problem is converted into a small linear one by applying a contour integral method. Adequate modifications are suggested to improve the efficiency of the contour integral method and avoid missing the eigenvalues of interest. The Burton–Miller formulation is applied to tackle the fictitious eigenfrequency problem of the BEM, and the optimal choice of its coupling parameter is investigated for the coupled FE–BE method. Numerical examples are given and discussed to demonstrate the effectiveness and accuracy of the developed FE–BE method. Copyright © 2016 John Wiley & Sons, Ltd.