The Experts below are selected from a list of 12612 Experts worldwide ranked by ideXlab platform
Changhong Hu - One of the best experts on this subject based on the ideXlab platform.
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Simulation of violent Free Surface Flow by AMR method
Journal of Hydrodynamics, 2018Co-Authors: Changhong HuAbstract:A novel CFD approach based on adaptive mesh refinement (AMR) technique is being developed for numerical simulation of violent Free Surface Flows. CIP method is applied to the Flow solver and tangent of hyperbola for interface capturing with slope weighting (THINC/SW) scheme is implemented as the Free Surface capturing scheme. The PETSc library is adopted to solve the linear system. The linear solver is redesigned and modified to satisfy the requirement of the AMR mesh topology. In this paper, our CFD method is outlined and newly obtained results on numerical simulation of violent Free Surface Flows are presented.
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Free Surface Flow impacting on an elastic structure: Experiment versus numerical simulation
Applied Ocean Research, 2015Co-Authors: Kangping Liao, Changhong Hu, Makoto SueyoshiAbstract:Abstract The purpose of this study is to investigate the phenomenon of Free Surface Flow impacting on elastic structures, which is a research topic of great interest in ship and ocean engineering. A series of quasi two-dimensional experiments on dam-break with an elastic plate are conducted. The main features of Free Surface Flow impacting on elastic structures including large impacting force, structural vibration, violent Free Surface Flow, are investigated. The coupled FDM–FEM method developed by the authors is applied for numerical simulation of such dam-break problem. Extensive analysis and discussion based on the comparisons between experimental data and numerical results are made and presented in this paper.
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A coupled FDM–FEM method for Free Surface Flow interaction with thin elastic plate
Journal of Marine Science and Technology, 2013Co-Authors: Kangping Liao, Changhong HuAbstract:A partitioned approach by the coupling finite difference method (FDM) and the finite element method (FEM) is developed for simulating the interaction between Free Surface Flow and a thin elastic plate. The FDM, in which the constraint interpolation profile method is applied, is used for solving the Flow field in a regular fixed Cartesian grid, and the tangent of the hyperbola for interface capturing with the slope weighting scheme is used for capturing Free Surface. The FEM is used for solving structural deformation of the thin plate. A conservative momentum-exchange method, based on the immersed boundary method, is adopted to couple the FDM and the FEM. Background grid resolution of the thin plate in a regular fixed Cartesian grid is important to the computational accuracy by using this method. A virtual structure method is proposed to improve the background grid resolution of the thin plate. Both of the Flow solver and the structural solver are carefully tested and extensive validations of the coupled FDM–FEM method are carried out on a benchmark experiment, a rolling tank sloshing with a thin elastic plate.
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a coupled fdm fem method for Free Surface Flow interaction with thin elastic plate
Journal of Marine Science and Technology, 2013Co-Authors: Kangping Liao, Changhong HuAbstract:A partitioned approach by the coupling finite difference method (FDM) and the finite element method (FEM) is developed for simulating the interaction between Free Surface Flow and a thin elastic plate. The FDM, in which the constraint interpolation profile method is applied, is used for solving the Flow field in a regular fixed Cartesian grid, and the tangent of the hyperbola for interface capturing with the slope weighting scheme is used for capturing Free Surface. The FEM is used for solving structural deformation of the thin plate. A conservative momentum-exchange method, based on the immersed boundary method, is adopted to couple the FDM and the FEM. Background grid resolution of the thin plate in a regular fixed Cartesian grid is important to the computational accuracy by using this method. A virtual structure method is proposed to improve the background grid resolution of the thin plate. Both of the Flow solver and the structural solver are carefully tested and extensive validations of the coupled FDM–FEM method are carried out on a benchmark experiment, a rolling tank sloshing with a thin elastic plate.
Jan Vierendeels - One of the best experts on this subject based on the ideXlab platform.
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partitioned simulation of the interaction between an elastic structure and Free Surface Flow
Computer Methods in Applied Mechanics and Engineering, 2010Co-Authors: Joris Degroote, Sebastiaan Annerel, Peter Bruggeman, Antonio Soutoiglesias, Wim Van Paepegem, Jan VierendeelsAbstract:Currently, the interaction between Free Surface Flow and an elastic structure is simulated with monolithic codes which calculate the deformation of the structure and the liquid–gas Flow simultaneously. In this work, this interaction is calculated in a partitioned way with a separate Flow solver and a separate structural solver using the interface quasi-Newton algorithm with approximation for the inverse of the Jacobian from a least-squares model (IQN-ILS). The interaction between an elastic beam and a sloshing liquid in a rolling tank is calculated and the results agree well with experimental data. Subsequently, the impact of both a rigid cylinder and a flexible composite cylinder on a water Surface is simulated to assess the effect of slamming on the components of certain wave-energy converters. The impact pressure on the bottom of the rigid cylinder is nearly twice as high as on the flexible cylinder, which emphasizes the need for fluid–structure interaction calculations in the design process of these wave-energy converters. For both the rolling tank simulations and the impact simulations, grid refinement is performed and the IQN-ILS algorithm requires the same number of iterations on each grid. The simulations on the coarse grid are also executed using Gauss-Seidel coupling iterations with Aitken relaxation which requires significantly more coupling iterations per time step.
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Partitioned simulation of the interaction between an elastic structure and Free Surface Flow
Computer Methods in Applied Mechanics and Engineering, 2010Co-Authors: Joris Degroote, Sebastiaan Annerel, Peter Bruggeman, A. Souto-iglesias, Wim Van Paepegem, Jan VierendeelsAbstract:Currently, the interaction between Free Surface Flow and an elastic structure is simulated with monolithic codes which calculate the deformation of the structure and the liquid-gas Flow simultaneously. In this work, this interaction is calculated in a partitioned way with a separate Flow solver and a separate structural solver using the interface quasi-Newton algorithm with approximation for the inverse of the Jacobian from a least-squares model (IQN-ILS). The interaction between an elastic beam and a sloshing liquid in a rolling tank is calculated and the results agree well with experimental data. Subsequently, the impact of both a rigid cylinder and a flexible composite cylinder on a water Surface is simulated to assess the effect of slamming on the components of certain wave-energy converters. The impact pressure on the bottom of the rigid cylinder is nearly twice as high as on the flexible cylinder, which emphasizes the need for fluid-structure interaction calculations in the design process of these wave-energy converters. For both the rolling tank simulations and the impact simulations, grid refinement is performed and the IQN-ILS algorithm requires the same number of iterations on each grid. The simulations on the coarse grid are also executed using Gauss-Seidel coupling iterations with Aitken relaxation which requires significantly more coupling iterations per time step. © 2010 Elsevier B.V.
Tomonori Yamada - One of the best experts on this subject based on the ideXlab platform.
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Parallel analysis system for Free-Surface Flow using MPS method with explicitly represented polygon wall boundary model
Computational Particle Mechanics, 2019Co-Authors: Naoto Mitsume, Tomonori Yamada, Shinobu YoshimuraAbstract:This study develops a parallel solver of Free-Surface Flow based on a mesh-Free particle method, the explicit MPS method, with polygon boundary representation. We adopt the explicitly represented polygon (ERP) wall boundary model, which expresses wall boundaries as arbitrarily shaped triangular polygons. A bucket-based domain decomposition algorithm for dynamic load balancing is expanded to the polygon-based computation of the ERP model. The validity and parallel efficiency of the developed solver are tested by analyzing a dam break problem, and the numerical results are compared with experimental results. Our developed solver can simplify the evaluation of the integrity of coastal structures since it can be easily connected to finite element analyses of the structures.
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Inundation Simulation Coupling Free Surface Flow and Structures
Springer Tracts in Mechanical Engineering, 2016Co-Authors: Naoto Mitsume, Kaneyoshi Murotani, Shinobu Yoshimura, Tomonori YamadaAbstract:Water-related disasters such as tsunamis, storm surges, and floods involve fluid–structure interaction (FSI) problems with Free Surface Flow. Since failures of artifacts are caused due to inundation, water forces and impact forces by floating objects, simulation of such problems has great importance to design for safety and robustness.In this chapter, we present a robust and efficient coupled method for fluid–structure interaction with violent Free Surface Flow, named the MPS-FE method and its improved method. The MPS-FE method adopts the finite element (FE) method for structure computation and the moving particle semi-implicit/simulation (MPS) method for fluid computation involving Free Surface Flow. The conventional MPS-FE method, in which MPS wall boundary particles and finite elements are overlapped in order to exchange information at fluid–structure interface, is not versatile and reduces the advantages of software modularity. We developed a non-overlapping approach in which the interface in the fluid computation corresponds to that in the structure computation through an MPS polygon wall model. The accuracy of the improved MPS-FE method was verified by solving a dam break problem with an elastic obstacle and by comparing the result obtained with that of the conventional MPS-FE method and other methods.
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mps fem partitioned coupling approach for fluid structure interaction with Free Surface Flow
International Journal of Computational Methods, 2014Co-Authors: Naoto Mitsume, Kaneyoshi Murotani, Shinobu Yoshimura, Tomonori YamadaAbstract:Fluid–structure interaction analysis involving Free Surface Flow has been investigated using mesh-based methods or mesh-Free particle methods. While mesh-based methods have several problems in dealing with the fragmentation of geometry and moving interfaces and with the instability of nonlinear advective terms, mesh-Free particle methods can deal with Free Surface and moving boundary relatively easily. In structural analyses, the finite element method, which is a mesh-based method, has been investigated extensively and can accurately deal with not only elastic problems but also plastic and fracture problems. Thus, the present study proposes a partitioned coupling strategy for fluid–structure interaction problems involving Free Surfaces and moving boundaries that calculates the fluid domain using the moving particle simulation method and the structure domain using the finite element method. As the first step, we apply a conventional serial staggered algorithm as a weak coupling scheme. In addition, for the verification of the proposed method, the problem of a breaking dam on an elastic wall is calculated, and the results are compared with the results obtained by other methods.
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MPS–FEM PARTITIONED COUPLING APPROACH FOR FLUID–STRUCTURE INTERACTION WITH Free Surface Flow
International Journal of Computational Methods, 2014Co-Authors: Naoto Mitsume, Kaneyoshi Murotani, Shinobu Yoshimura, Tomonori YamadaAbstract:Fluid-structure interaction analysis involving Free Surface Flow has been investigated using mesh-based methods or mesh-Free particle methods. While mesh-based methods have several problems in dealing with the fragmentation of geometry and moving interfaces and with the instability of nonlinear advective terms, mesh-Free particle methods can deal with Free Surface and moving boundary relatively easily. In structural analyses, the finite element method, which is a mesh-based method, has been investigated extensively and can accurately deal with not only elastic problems but also plastic and fracture problems. Thus, the present study proposes a partitioned coupling strategy for fluid-structure interaction problems involving Free Surfaces and moving boundaries that calculates the fluid domain using the moving particle simulation method and the structure domain using the finite element method. As the first step, we apply a conventional serial staggered algorithm as a weak coupling scheme. In addition, for the verification of the proposed method, the problem of a breaking dam on an elastic wall is calculated, and the results are compared with the results obtained by other methods. © 2014 World Scientific Publishing Company.
Kangping Liao - One of the best experts on this subject based on the ideXlab platform.
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Free Surface Flow impacting on an elastic structure: Experiment versus numerical simulation
Applied Ocean Research, 2015Co-Authors: Kangping Liao, Changhong Hu, Makoto SueyoshiAbstract:Abstract The purpose of this study is to investigate the phenomenon of Free Surface Flow impacting on elastic structures, which is a research topic of great interest in ship and ocean engineering. A series of quasi two-dimensional experiments on dam-break with an elastic plate are conducted. The main features of Free Surface Flow impacting on elastic structures including large impacting force, structural vibration, violent Free Surface Flow, are investigated. The coupled FDM–FEM method developed by the authors is applied for numerical simulation of such dam-break problem. Extensive analysis and discussion based on the comparisons between experimental data and numerical results are made and presented in this paper.
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A coupled FDM–FEM method for Free Surface Flow interaction with thin elastic plate
Journal of Marine Science and Technology, 2013Co-Authors: Kangping Liao, Changhong HuAbstract:A partitioned approach by the coupling finite difference method (FDM) and the finite element method (FEM) is developed for simulating the interaction between Free Surface Flow and a thin elastic plate. The FDM, in which the constraint interpolation profile method is applied, is used for solving the Flow field in a regular fixed Cartesian grid, and the tangent of the hyperbola for interface capturing with the slope weighting scheme is used for capturing Free Surface. The FEM is used for solving structural deformation of the thin plate. A conservative momentum-exchange method, based on the immersed boundary method, is adopted to couple the FDM and the FEM. Background grid resolution of the thin plate in a regular fixed Cartesian grid is important to the computational accuracy by using this method. A virtual structure method is proposed to improve the background grid resolution of the thin plate. Both of the Flow solver and the structural solver are carefully tested and extensive validations of the coupled FDM–FEM method are carried out on a benchmark experiment, a rolling tank sloshing with a thin elastic plate.
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a coupled fdm fem method for Free Surface Flow interaction with thin elastic plate
Journal of Marine Science and Technology, 2013Co-Authors: Kangping Liao, Changhong HuAbstract:A partitioned approach by the coupling finite difference method (FDM) and the finite element method (FEM) is developed for simulating the interaction between Free Surface Flow and a thin elastic plate. The FDM, in which the constraint interpolation profile method is applied, is used for solving the Flow field in a regular fixed Cartesian grid, and the tangent of the hyperbola for interface capturing with the slope weighting scheme is used for capturing Free Surface. The FEM is used for solving structural deformation of the thin plate. A conservative momentum-exchange method, based on the immersed boundary method, is adopted to couple the FDM and the FEM. Background grid resolution of the thin plate in a regular fixed Cartesian grid is important to the computational accuracy by using this method. A virtual structure method is proposed to improve the background grid resolution of the thin plate. Both of the Flow solver and the structural solver are carefully tested and extensive validations of the coupled FDM–FEM method are carried out on a benchmark experiment, a rolling tank sloshing with a thin elastic plate.
Yasser M Ahmed - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation for the Free Surface Flow around a complex ship hull form at different froude numbers
alexandria engineering journal, 2011Co-Authors: Yasser M AhmedAbstract:Abstract The incompressible turbulent Free Surface Flow around the complex hull form of the DTMB 5415 model at two different speeds has been numerically simulated using the RANSE code CFX. The Volume of Fluid method (VOF) has been used with CFX for capturing the Free Surface Flow around the ship model at the two speeds. The simulation conditions are the ones for which experimental and numerical results exist. The standard k–ɛ turbulence model has been used in CFX code. The grid generator ICEM CFD has been used for building the hybrid grid for the RANSE code solver. The results compare well with the available experimental and numerical data.
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simulation of Free Surface Flow around a vlcc hull using viscous and potential Flow methods
Ocean Engineering, 2009Co-Authors: Yasser M Ahmed, Guedes C SoaresAbstract:Abstract Numerical simulations have been carried out to determine the incompressible Free Surface Flow around a VLCC hull form for which experimental results are available. A commercial viscous Flow finite volume code using the two-phase Eulerian–Eulerian fluid approach and a potential Flow code based on the Rankine source method have been used in this study. The simulation conditions are the ones for which experimental results exist. The shear stress transport (SST) turbulence model has been used in the viscous Flow code. A tetrahedral unstructured grid was used with the viscous Flow code for meshing the computational domain, while quadrilateral structural patches were used with the potential Flow code for meshing the VLCC hull Surface and the water Surface around it. The results compare well with the available experimental data and they allow an understanding of the differences that can be expected from viscous and potential Flow methods as a result of their different mathematical formulations, which make their complementary application useful for determining the total ship resistance.
