P.A. Trapper¹, P.Z. Bar-Yoseph²

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.1, pp. 19-47, 2014, DOI:10.3970/cmes.2014.103.019

Abstract The space-time discontinuous Galerkin method for multi-dimensional nonlinear hyperbolic systems is enhanced with a generalized technique for splitting a flux vector that is not limited to the homogeneity property of the flux. This technique, based on the flux’s characteristic decomposition, extends the scope of the method’s applicability to a wider range of problems, including elastodynamics. The method is used for numerical solution of a number of representative problems based on models of vibrating string and vibrating rod that involve the propagation of a sharp front through the solution domain. More >

H. S. Shukla¹, Mohammad Tamsir¹, Vineet K. Srivastava², Jai Kumar³

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.1, pp. 1-17, 2014, DOI:10.3970/cmes.2014.103.001

Abstract The objective of this article is to carry out an approximate analytical solution of the time fractional order Cauchy-reaction diffusion equation by using a semi analytical method referred as the fractional-order reduced differential transform method (FRDTM). The fractional derivative is illustrated in the Caputo sense. The FRDTM is very efficient and effective powerful mathematical tool for solving wide range of real world physical problems by providing an exact or a closed approximate solution of any differential equation arising in engineering and allied sciences. Four test numerical examples are provided to validate and illustrate the efficiency of FRDTM. More >

Annamaria Mazzia¹, Giorgio Pini¹, Flavio Sartoretto²

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.6, pp. 475-497, 2014, DOI:10.3970/cmes.2014.102.475

Abstract Meshless Local Petrov Galerkin (MLPG) methods are pure meshless techniques for solving Partial Differential Equations. One of pure meshless methods main applications is for implementing Adaptive Discretization Techniques. In this paper, we describe our fresh node–wise refinement technique, based upon estimations of the “local” Total Variation of the approximating function. We numerically analyze the accuracy and efficiency of our MLPG–based refinement. Solutions to test Poisson problems are approximated, which undergo large variations inside small portions of the domain. We show that 2D problems can be accurately solved. The gain in accuracy with respect to uniform discretizations is shown to be… More >

M.A.L. Martins¹, E.N. Lages¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.6, pp. 449-474, 2014, DOI:10.3970/cmes.2014.102.449

Abstract Embedded anchors have been widely used in offshore operations, and they are known to be effective and economical solutions to anchoring problems. Aiming at contributing to the definition and understanding of the embedded mooring line behavior, this paper expands the formulation adopted at DNV Recommended Practices, for two-dimensional modeling of the interaction between the seabed and the anchor line, to three-dimensional analysis. The formulation here presented, within an elegant differential geometry approach, can now model even out of plane lines. A reference problem is then defined and solved using the obtained governing equations. Corresponding equations are implemented and solved numerically… More >

Y.C. Shiah¹, C.L. Tan^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.6, pp. 425-447, 2014, DOI:10.3970/cmes.2014.102.425

Abstract Green’s functions, or fundamental solutions, are necessary items in the formulation of the boundary integral equation (BIE), the analytical basis of the boundary element method (BEM). In the formulation of the BEM for 3D general anisotropic elasticity, considerable attention has been devoted to developing efficient algorithms for computing these quantities over the years. The mathematical complexity of this Green’s function has also posed an obstacle in the development of this numerical method to treat problems of 3D anisotropic thermoelasticity. This is because thermal effects manifest themselves as an additional domain integral in the integral equation; this has implications for the… More >

S. Hamada¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.5, pp. 407-424, 2014, DOI:10.3970/cmes.2014.102.407

Abstract The voxel-based indirect boundary element method (IBEM) combined with the Laplace-kernel fast multipole method (FMM) is capable of analyzing relatively large-scale problems. A typical application of the IBEM is the electric field analysis in virtual-human models such as the model called Duke provided by the foundation for research on information technologies in society (IT’IS Foundation). An important property of voxel-version Duke models is that they have various voxel sizes but the same structural feature. This property is useful for examining the O(N) and O(D²) dependencies of the calculation times and the amount of memory required by the FMM-IBEM, where N… More >

A. Sellier¹, S. H. Aydin², M. Tezer-Sezgin³

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.5, pp. 393-406, 2014, DOI:10.3970/cmes.2014.102.393

Abstract The fundamental free-space 2D steady creeping MHD flow produced by a concentrated point force of strength g located at a so-called source point x₀ in an unbounded conducting Newtonian liquid with uniform viscosity µ and conductivity σ > 0 subject to a prescribed uniform ambient magnetic field B = Be₁ is analytically obtained. More precisely, not only the produced flow pressure p and velocity u but also the resulting stress tensor field σ are expressed at any observation point x ≠ x₀ in terms of usual modified Bessel functions, the vectors g, x-x₀ and the so-called Hartmann layer thickness d… More >