Home / Journals / CMES / Vol.41, No.2, 2009
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  • Open Access

    ARTICLE

    An Atomistic Study of Elliptic Cross-Sectional Nanosprings

    I-L. Chang1, M.-S. Yeh1
    CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.2, pp. 95-106, 2009, DOI:10.3970/cmes.2009.041.095
    Abstract One-dimensional copper nanospring with elliptic cross section was studied using molecular statics method based on minimum energy consideration. Various geometric sizes (wire semi-axis length, radius, pitch) and crystal orientations of nanosprings were systematically modeled to investigate the size dependence of elastic properties for both normal and binormal nanosprings. It was observed that as the wire semi-axis increases, and the radius and pitch decrease, the nanospring stiffness would increase irrespective to the crystal orientations. Moreover, it was noticed that the normal nanosprings always behave stiffer than the binormal ones for the same radius, pitch and cross-sectional geometry in our study. More >

  • Open Access

    ARTICLE

    Recirculation of Viscous Incompressible Flows in Enclosures

    Elsa Báez, Alfredo Nicolás1
    CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.2, pp. 107-130, 2009, DOI:10.3970/cmes.2009.041.107
    Abstract The unsteady Navier-Stokes equations in primitive variables that govern viscous incompressible fluid flow are numerically solved by a simple projection method which involves an operator splitting technique of three steps in the time discretization process. The numerical scheme does not involve any iteration, is independent of the spatial dimension, and its costly part relies on the solution of elliptic problems for which very efficient solvers exist regardless of the spatial discretization. The scheme is tested with the well known two-dimensional lid-driven cavity problem at moderate and high Reynolds numbers Re in the range 400 ≤ Re ≤ 15000. For moderate… More >

  • Open Access

    ARTICLE

    Numerical Modeling of Short-Pulse Laser Interactions with Multi-Layered Thin Metal Films

    E. Majchrzak1, B. Mochnacki2, A. L. Greer3, J. S. Suchy4
    CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.2, pp. 131-146, 2009, DOI:10.3970/cmes.2009.041.131
    Abstract Multi-layered thin metal film subjected to a short-pulse laser heating is considered. Mathematical description of the process discussed bases on the equation in which there appear the relaxation time and the thermalization time (dual-phase-lag-model). In this study we develop a three level implicit finite difference scheme for numerical modelling of heat transfer in non-homogeneous metal film. At the interfaces an ideal contact between successive layers is assumed. At the stage of computations a solution of only one three-diagonal linear system corresponds to transition from time t to t + Δt. The mathematical model, numerical algorithm and examples of computations are… More >

  • Open Access

    ARTICLE

    An automated approach for solution based mesh adaptation to enhance numerical accuracy for a given number of grid cells Applied to steady flow on hexahedral grids

    Peter Lucas1, Alexander H. van Zuijlen1, Hester Bijl1
    CMES-Computer Modeling in Engineering & Sciences, Vol.41, No.2, pp. 147-176, 2009, DOI:10.3970/cmes.2009.041.147
    Abstract Mesh adaptation is a fairly established tool to obtain numerically accurate solutions for flow problems. Computational efficiency is, however, not always guaranteed for the adaptation strategies found in literature. Typically excessive mesh growth diminishes the potential efficiency gain. This paper, therefore, extends the strategy proposed by [Aftosmis and Berger (2002)] to compute the refinement threshold. The extended strategy computes the refinement threshold based on a user desired number of grid cells and adaptations, thereby ensuring high computational efficiency. Because our main interest is flow around wind turbines, the adaptation strategy has been optimized for flow around wind turbine airfoils. The… More >

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