C. Moulinec¹, R. Issa², J.-C. Marongiu³, D. Violeau⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.25, No.3, pp. 133-148, 2008, DOI:10.3970/cmes.2008.025.133

Abstract The gridless Smoothed Particle Hydrodynamics (SPH) numerical method is preferably used in Computational Fluid Dynamics (CFD) to simulate complex flows with one or several convoluted free surfaces. This type of flows requires distorted meshes with classical Eulerian mesh-based methods or very fine meshes with Volume of Fluid method. Few 3-D SPH simulations have been carried out to our knowlegde so far, mainly due to prohibitive computational investment since the number of particles required in 3-D is usually too large to be handled by a single processor. In this paper, a parallel 3-D SPH code is presented. Parallelisation validation is discussed… More >

S. Namilae¹, U. Ch,ra², A Srinivasan³, N. Ch,ra⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 189-202, 2007, DOI:10.3970/cmes.2007.022.189

Abstract Molecular dynamics (MD) simulations play an important predictive role in understanding the behavior of nanoscale systems. In this paper, parallel MD simulations are used to understand the mechanical behavior of interfaces in CNT based composites. We present an algorithm for parallel implementation of MD simulations of carbon nanotube (CNT) based systems using reactive bond order potentials. We then use that algorithm to model the CNT-polymer interfaces with various levels of interaction as (a) described only by long range Van Der Waals interactions (b) chemically bonded with fixed matrix and (c) chemically bonded with matrix explicitly modeled. It is shown that… More >

J. M. F. Trindade¹, J. C. F. Pereira²

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.1, pp. 1-10, 2007, DOI:10.3970/cmes.2007.020.001

Abstract In this paper, we discuss the efficiency and speed-up of parallel-in-time calculations of the unsteady incompressible Navier-Stokes equations in a PC-cluster. The parallel-in-time method is based on the alternate use of coarse global sequential solvers with fine local parallel ones in an iterative predictor-corrector fashion. Therefore, the efficiency of parallel calculations is strongly dependent on the number of iterations required for convergence. The one-dimensional scalar transport equation and the two-dimensional incompressible unsteady form of the Navier-Stokes equations were used to conduct numerical experiments to derive some conclusions concerning the accuracy and convergence of the iterative method. A simple performance model… More >

Y.F. Nie¹, S. Chang¹, X.K. Fan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.2, pp. 135-144, 2007, DOI:10.3970/cmes.2007.019.135

Abstract A new parallel mechanism for Node-based Seamless Finite Element Method was proposed in this paper, which possessed the following three prominent points: realizing the workload balance for the parallel processes naturally, achieving synchronization of all the schedules under complex parallel environment, and filling up the gap between pre-processing and main processing. To support the scheme, three specific solutions of the parallel mechanism were proposed in this paper, all of which achieved the highly efficient parallel seamless connection between the FEM mesh generation process and structure analysis process. Two of the three schemes, i.e. dynamic scheme and self-adaptive scheme, enabled both… More >

J. Ma¹, H. Lu¹, B. Wang¹, S. Roy¹, R. Hornung², A. Wissink², R. Komanduri^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.2, pp. 135-152, 2005, DOI:10.3970/cmes.2005.008.135

Abstract In the simulation of a wide range of mechanics problems including impact/contact/penetration and fracture, the material point method (MPM), Sulsky, Zhou and Shreyer (1995), demonstrated its computational capabilities. To resolve alternating stress sign and instability problems associated with conventional MPM, Bardenhagen and Kober (2004) introduced recently the generalized interpolation material point (GIMP) method and implemented for one-dimensional simulations. In this paper we have extended GIMP to 2D and applied to simulate simple tension and indentation problems. For simulations spanning multiple length scales, based on the continuum mechanics approach, we present a parallel GIMP computational method using the Structured Adaptive Mesh… More >

J. Bielak¹, O. Ghattas², E.-J. Kim³

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.2, pp. 99-112, 2005, DOI:10.3970/cmes.2005.010.099

Abstract We present a parallel octree-based finite element method for large-scale earthquake ground motion simulation in realistic basins. The octree representation combines the low memory per node and good cache performance of finite difference methods with the spatial adaptivity to local seismic wavelengths characteristic of unstructured finite element methods. Several tests are provided to verify the numerical performance of the method against Green's function solutions for homogeneous and piecewise homogeneous media, both with and without anelastic attenuation. A comparison is also provided against a finite difference code and an unstructured tetrahedral finite element code for a simulation of the 1994 Northridge… More >

M.Ganesh¹, D. Sheen²

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.2, pp. 183-194, 2001, DOI:10.3970/cmes.2001.002.183

Abstract A parallel numerical algorithm is introduced and analyzed for solving inhomogeneous initial-boundary value parabolic problems. The scheme is based on the method recently introduced in Sheen, Sloan, and Thomée (2000) for homogeneous problems. We give a method based on a suitable choice of multiple parameters. Our scheme allows one to compute solutions in a wide range of time. Instead of using a standard time-marching method, which is not easily parallelizable, we take the Laplace transform in time of the parabolic problems. The resulting elliptic problems can be solved in parallel. Solutions are then computed by a discrete inverse Laplace transformation.… More >

Z. Chen¹, W. Hu¹, E.P. Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.4, pp. 57-62, 2000, DOI:10.3970/cmes.2000.001.509

Abstract To simulate the dynamic failure evolution without using nonlocal terms in the strain-stress space, a damage diffusion equation is formulated with the use of a combined damage/plasticity model that was primarily applied to the case of rock fragmentation. A vectorized model solver is developed for large-scale simulation. Two-dimensional sample problems are considered to illustrate the features of the proposed solution procedure. It appears that the proposed approach is effective in simulating the evolution of localization, with parallel computing, in a single computational domain involving different lower-order governing differential equations. More >

J.R. Lin¹, T.L. Chou², L.J. Liang², M.C. Lin², P.H. Lee²

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.1, pp. 49-61, 2015, DOI:10.3970/fdmp.2015.011.049

Abstract The characteristics of a hydromagnetic non-Newtonian squeeze film formed between parallel rectangular plates under the application on an external magnetic field are investigated. A specific hydromagnetic non-Newtonian Reynolds equation is derived via pplication of the hydromagnetic flow theory together with the micro-continuum theory. It is found that the coupled effects of electrically conducting fluids and micropolar fluids result in a higher load capacity and a longer approaching time with respect to the non-conducting Newtonian case. These improved characteristics become more pronounced as the magnetic Hartmann parameter, the coupling parameter, and the fluid-gap parameter are increased. More >

F. Mechighel^1,2, M. El Ganaoui¹, M. Kadja², B. Pateyron³, S. Dost⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.4, pp. 313-330, 2009, DOI:10.3970/fdmp.2009.005.313

Abstract A numerical study has been carried out to investigate the three-dimen -sional buoyant flow in a parallelepiped box heated from below and partially from the two sidewalls (a configuration commonly used for solidification problems and crystal growth systems). Attention has been paid, in particular, to phenomena of symmetry breaking and transition to unsteady non-symmetric convection for a low Prandtl number fluid (Pr=0.01). The influence of an applied horizontal magnetic field on the stability properties of the flow has been also considered. Results obtained may be summarized as follows: In the absence of magnetic field and for relatively small values of… More >