Home / Journals / CMES / Vol.119, No.1, 2019
Table of Content
  • Open Access

    EDITORIAL

    Preface: Simulation of Fluid-Structure Interaction Problems

    Zhilin Li1, X.Sheldon Wang2, ∗, LucyT. Zhang3
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 1-3, 2019, DOI:10.32604/cmes.2019.06635
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract This article has no abstract. More >

  • Open Access

    ARTICLE

    Model Studies of Fluid-Structure Interaction Problems

    X.Sheldon Wang1,∗, Ye Yang2, Tao Wu2
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 5-34, 2019, DOI:10.32604/cmes.2019.04204
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract In this work, we employ fluid-structure interaction (FSI) systems with immersed flexible structures with or without free surfaces to explore both Singular Value Decomposition (SVD)-based model reduction methods and mode superposition methods. For acoustoelastic FSI systems, we adopt a three-field mixed finite element formulation with displacement, pressure, and vorticity moment unknowns to effectively enforce the irrotationality constraint. We also propose in this paper a new Inf-Sup test based on the lowest non-zero singular value of the coupling matrix for the selection of reliable sets of finite element discretizations for displacement and pressure as well as vorticity moment. Our numerical examples… More >

  • Open Access

    ARTICLE

    Distributed Lagrange Multiplier/Fictitious Domain Finite Element Method for a Transient Stokes Interface Problem with Jump Coefficients

    Andrew Lundberg1, Pengtao Sun1,∗, Cheng Wang2, Chen-song Zhang3
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 35-62, 2019, DOI:10.32604/cmes.2019.04804
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract The distributed Lagrange multiplier/fictitious domain (DLM/FD)-mixed finite element method is developed and analyzed in this paper for a transient Stokes interface problem with jump coefficients. The semi- and fully discrete DLM/FD-mixed finite element scheme are developed for the first time for this problem with a moving interface, where the arbitrary Lagrangian-Eulerian (ALE) technique is employed to deal with the moving and immersed subdomain. Stability and optimal convergence properties are obtained for both schemes. Numerical experiments are carried out for different scenarios of jump coefficients, and all theoretical results are validated. More >

  • Open Access

    ARTICLE

    An Augmented IB Method & Analysis for Elliptic BVP on Irregular Domains

    Zhilin Li1,∗, Baiying Dong2, Fenghua Tong3, Weilong Wang3
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 63-72, 2019, DOI:10.32604/cmes.2019.04635
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract The immersed boundary method is well-known, popular, and has had vast areas of applications due to its simplicity and robustness even though it is only first order accurate near the interface. In this paper, an immersed boundary-augmented method has been developed for linear elliptic boundary value problems on arbitrary domains (exterior or interior) with a Dirichlet boundary condition. The new method inherits the simplicity, robustness, and first order convergence of the IB method but also provides asymptotic first order convergence of partial derivatives. Numerical examples are provided to confirm the analysis. More >

  • Open Access

    ARTICLE

    A Simple FEM for Solving Two-Dimensional Diffusion Equation with Nonlinear Interface Jump Conditions

    Liqun Wang1, Songming Hou2, Liwei Shi3,∗
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 73-90, 2019, DOI:10.32604/cmes.2019.04581
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract In this paper, we propose a numerical method for solving parabolic interface problems with nonhomogeneous flux jump condition and nonlinear jump condition. The main idea is to use traditional finite element method on semi-Cartesian mesh coupled with Newton’s method to handle nonlinearity. It is easy to implement even though variable coefficients are used in the jump condition instead of constant in previous work for elliptic interface problem. Numerical experiments show that our method is about second order accurate in the L norm. More >

  • Open Access

    ARTICLE

    OpenIFEM: A High Performance Modular Open-Source Software of the Immersed Finite Element Method for Fluid-Structure Interactions

    Jie Cheng1, Feimi Yu1, Lucy T. Zhang1, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 91-124, 2019, DOI:10.32604/cmes.2019.04318
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract We present a high performance modularly-built open-source software - OpenIFEM. OpenIFEM is a C++ implementation of the modified immersed finite element method (mIFEM) to solve fluid-structure interaction (FSI) problems. This software is modularly built to perform multiple tasks including fluid dynamics (incompressible and slightly compressible fluid models), linear and nonlinear solid mechanics, and fully coupled fluid-structure interactions. Most of open-source software packages are restricted to certain discretization methods; some are under-tested, under-documented, and lack modularity as well as extensibility. OpenIFEM is designed and built to include a set of generic classes for users to adapt so that any fluid and… More >

  • Open Access

    ARTICLE

    An IB Method for Non-Newtonian-Fluid Flexible-Structure Interactions in Three-Dimensions

    Luoding Zhu1,∗
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 125-143, 2019, DOI:10.32604/cmes.2019.04828
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract Problems involving fluid flexible-structure interactions (FFSI) are ubiquitous in engineering and sciences. Peskin’s immersed boundary (IB) method is the first framework for modeling and simulation of such problems. This paper addresses a three-dimensional extension of the IB framework for non-Newtonian fluids which include power-law fluid, Oldroyd-B fluid, and FENE-P fluid. The motion of the non-Newtonian fluids are modelled by the lattice Boltzmann equations (D3Q19 model). The differential constitutive equations of Oldroyd-B and FENE-P fluids are solved by the D3Q7 model. Numerical results indicate that the new method is first-order accurate and conditionally stable. To show the capability of the new… More >

  • Open Access

    ARTICLE

    Multiscale Hybrid-Mixed Finite Element Method for Flow Simulation in Fractured Porous Media

    Philippe Devloo1, Wenchao Teng2, Chen-Song Zhang3,∗
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 145-163, 2019, DOI:10.32604/cmes.2019.04812
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract The multiscale hybrid-mixed (MHM) method is applied to the numerical approximation of two-dimensional matrix fluid flow in porous media with fractures. The two-dimensional fluid flow in the reservoir and the one-dimensional flow in the discrete fractures are approximated using mixed finite elements. The coupling of the two-dimensional matrix flow with the one-dimensional fracture flow is enforced using the pressure of the one-dimensional flow as a Lagrange multiplier to express the conservation of fluid transfer between the fracture flow and the divergence of the one-dimensional fracture flux. A zero-dimensional pressure (point element) is used to express conservation of mass where fractures… More >

  • Open Access

    ARTICLE

    An Immersed Method Based on Cut-Cells for the Simulation of 2D Incompressible Fluid Flows Past Solid Structures

    François Bouchon1, *, Thierry Dubois1, Nicolas James2
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 165-184, 2019, DOI:10.32604/cmes.2019.04841
    (This article belongs to this Special Issue: Recent Developments of Immersed Methods for Fluid-structure Interactions)
    Abstract We present a cut-cell method for the simulation of 2D incompressible flows past obstacles. It consists in using the MAC scheme on cartesian grids and imposing Dirchlet boundary conditions for the velocity field on the boundary of solid structures following the Shortley-Weller formulation. In order to ensure local conservation properties, viscous and convecting terms are discretized in a finite volume way. The scheme is second order implicit in time for the linear part, the linear systems are solved by the use of the capacitance matrix method for non-moving obstacles. Numerical results of flows around an impulsively started circular cylinder are… More >

  • Open Access

    ARTICLE

    A Novel Image Categorization Strategy Based on Salp Swarm Algorithm to Enhance Efficiency of MRI Images

    Mohammad Behrouzian Nejad1, Mohammad Ebrahim Shiri Ahmadabadi1, 2, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 185-205, 2019, DOI:10.32604/cmes.2019.01838
    Abstract The main target of this paper is presentation of an efficient method for MRI images classification so that it can be used to diagnose patients and non-patients. Image classification is one of the prominent subset topics of machine learning and data mining that the most important image technique is the auto-categorization of images. MRI images with high resolution and appropriate accuracy allow physicians to decide on the diagnosis of various diseases and treat them. The auto categorization of MRI images toward diagnosing brain diseases has been being used to accurately diagnose hospitals, clinics, physicians and medical research centers. In this… More >

  • Open Access

    ARTICLE

    Convergence Properties of Local Defect Correction Algorithm for the Boundary Element Method

    Godwin Kakuba1,∗, John M. Mango1, Martijn J.H. Anthonissen2
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 207-225, 2019, DOI:10.32604/cmes.2019.04269
    Abstract Sometimes boundary value problems have isolated regions where the solution changes rapidly. Therefore, when solving numerically, one needs a fine grid to capture the high activity. The fine grid can be implemented as a composite coarse-fine grid or as a global fine grid. One cheaper way of obtaining the composite grid solution is the use of the local defect correction technique. The technique is an algorithm that combines a global coarse grid solution and a local fine grid solution in an iterative way to estimate the solution on the corresponding composite grid. The algorithm is relatively new and its convergence… More >

  • Open Access

    ARTICLE

    Computational Modeling of Human Bicuspid Pulmonary Valve Dynamic Deformation in Patients with Tetralogy of Fallot

    Caili Li1, §, Christopher Baird2, Jing Yao3, Chun Yang4, Liang Wang5, Han Yu5, Tal Geva6, Dalin Tang5*, 7, §
    CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 227-244, 2019, DOI:10.32604/cmes.2019.06036
    Abstract Pulmonary valve stenosis (PVS) is one common right ventricular outflow tract obstruction problem in patients with tetralogy of Fallot (TOF). Congenital bicuspid pulmonary valve (BPV) is a condition of valvular stenosis, and the occurrence of congenital BPV is often associated with TOF. Dynamic computational models of normal pulmonary root (PR) with tri-leaflet and PR with BPV in patients with TOF were developed to investigate the effect of geometric structure of BPV on valve stress and strain distributions. The pulmonary root geometry included valvular leaflets, sinuses, interleaflet triangles and annulus. Mechanical properties of pulmonary valve leaflet were obtained from biaxial testing… More >

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