S. D. Akbarov^1,2, C. Ipek³

CMES-Computer Modeling in Engineering & Sciences, Vol.70, No.2, pp. 93-122, 2010, DOI:10.3970/cmes.2010.070.093

Abstract This paper studies the influence of the imperfectness of the interface conditions on the dispersion of the axisymmetric longitudinal waves in the pre-strained compound cylinder. The investigations are made within the framework of the piecewise homogeneous body model by utilizing the 3D linearized theory of elastic waves in elastic bodies with initial stresses. It is assumed that the layers of the compound cylinder are made from high elastic compressible materials and their elasticity relations are given through the harmonic potential. The shear spring type imperfectness of the interface conditions is considered and the degree of More >

C. Du¹, H. Bai², J. Qu³, X. Su^1,4

CMES-Computer Modeling in Engineering & Sciences, Vol.61, No.3, pp. 223-248, 2010, DOI:10.3970/cmes.2010.061.223

Abstract Second, or higher, order harmonics have great potential in fatigue life prediction. In this study, the dispersion properties of waves propagating in the nonlinear random media are investigated. An one dimensional nonlinear model based on the nonlinear Hikata stress-strain relation is used. We applied perturbation method, the Liouville transformation and the smoothing approximation method to solve the one dimensional nonlinear stochastic wave equation. We show easily that the dispersion equations for all higher order terms will be the same with the corresponding linear random medium by perturbation method. The linear stochastic equation with two random… More >

A. Papacharalampopoulos², G. F. Karlis², A. Charalambopoulos³, D. Polyzos⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.58, No.1, pp. 45-74, 2010, DOI:10.3970/cmes.2010.058.045

Abstract A Boundary Element Method (BEM) for solving two (2D) and three dimensional (3D) dynamic problems in materials with microstructural effects is presented. The analysis is performed in the frequency domain and in the context of Mindlin's Form II gradient elastic theory. The fundamental solution of the differential equation of motion is explicitly derived for both 2D and 3D problems. The integral representation of the problem, consisting of two boundary integral equations, one for displacements and the other for its normal derivative is exploited for the proposed BEM formulation. The global boundary of the analyzed domain More >

Surkay D. Akbarov^1,2,3, Mugan S. Guliev⁴, Ramazan Tekercioglu⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.1, pp. 1-32, 2010, DOI:10.3970/cmes.2010.055.001

Abstract Dispersion relations of axisymmetric longitudinal wave propagation in a finite pre-strained compound (bi-material) cylinder made from high elastic incompressible materials are investigated within the scope of a piecewise homogeneous body model utilizing three-dimensional linearized theory wave propagation in the initially stressed body. The materials of the inner and outer cylinders are assumed to be neo-Hookean. The numerical results regarding the influence of the initial strains in the inner and outer cylinders on the wave dispersion are presented and discussed. These results are obtained for the case where the material of the inner solid cylinder is More >

M. Chrigui^1,2, L. Schneider¹, A. Zghal², A. Sadiki¹, J. Janicka¹

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.4, pp. 399-408, 2010, DOI:10.3970/fdmp.2010.006.399

Abstract This paper deals with the numerical simulation of droplet dispersion and evaporation within an LPP (Lean Premix Prevaporized) burner. The Eulerian-Lagrangian approach was used for this purpose, and a fully two way-coupling was accounted for. For the phase transition, a non-equilibrium evaporation model was applied that differs strongly from the equilibrium one where there are high evaporation rates. The non-equilibrium conditions were fulfilled in the investigated configuration, as the droplets at the inlet had a mean diameter of 50mm. The numerical results of water droplet velocities, corresponding fluctuations, and diameters were compared with experimental data. More >

A. Radhouane¹, N. Mahjoub Said¹, H. Mhiri¹, G. Le Palec², P. Bournot²

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.4, pp. 385-398, 2010, DOI:10.3970/fdmp.2010.006.385

Abstract "Twin jets in crossflow" is a complex configuration that raises an increasing interest due to its presence in various common applications such as chimney stacks, film cooling, VSTOL aircrafts, etc... In the present paper, the twin jets were arranged inline with an oncoming crossflow;they were also inclined which resulted in similar elliptic cross sections of the nozzles' exits. The exploration of the flows in interaction was carried out numerically by means of the finite volume method together with the second order turbulent closure model, namely the Reynolds stress Model (RSM), and a non uniform grid… More >

L.L. Zhu^1,2,3, X.J. Zheng^1,2

CMC-Computers, Materials & Continua, Vol.18, No.3, pp. 301-320, 2010, DOI:10.3970/cmc.2010.018.301

Abstract The phonon properties of spatially confined nanofilms under the preexisting stress fields are investigated theoretically by accounting for the confinement effects and acoustoelastic effects. Due to the spatial confinement in low-dimensional structures, the phonon dispersion relations, phonon group velocities as well as the phonon density of states are of significant difference with the ones in bulk structures. Here, the continuum elasticity theory is made use of to determine the phonon dispersion relations of shear modes (SH), dilatational modes (SA) and the flexural modes (AS), thus to analyze the contribution of stress fields on the phonon More >

Chih-Wen Chang¹, Chein-Shan Liu²

CMC-Computers, Materials & Continua, Vol.17, No.1, pp. 19-40, 2010, DOI:10.3970/cmc.2010.017.019

Abstract In this study, we employ a semi-analytical approach to solve a two-dimensional advection-dispersion equation (ADE) for identifying the contamination problems. First, the Fourier series expansion technique is used to calculate the concentration field C(x, y, t) at any time t < T. Then, we ponder a direct regularization by adding an extra termaC(x, y, 0) on the final time data C(x, y, T), to reach a second-kind Fredholm integral equation. The termwise separable property of kernel function allows us obtaining a closed-form solution of the Fourier coefficients. A strategy to choose the regularization parameter is More >

Darrell W. Pepper¹, Xiuling Wang²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.13, No.1, pp. 15-22, 2009, DOI:10.3970/icces.2009.013.015

Abstract A meshless method for simulating indoor contaminant dispersion within buildings and rooms has been developed. The approach utilizes the advantages of the meshless method by distributing collocation points and different order radial basis functions according to the computational domain and evolving numerical solution. The numerical scheme yields fast convergence and high accuracy necessary for providing quick assessments of contamination transport within enclosures. More >

Xia Yuan¹, Wu Jichun², Zhou Luying³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.2, pp. 117-126, 2009, DOI:10.3970/icces.2009.009.117

Abstract This paper establishes a difference approximation on time-space fractional advection-dispersion equations. Based on the difference approximation an ideal numerical example has been solved, and the result is compared with the one of the rigorous time fractional advection-dispersion equation and the rigorous space fractional advection-dispersion equation respectively. The results show: when time fractional order parameter γ=1 or space fractional order parameter α=2, the numerical calculation result of the time-space fractional advection-dispersion equations is in accordance with that of the rigorous time fractional advection-dispersion equation or the rigorous space fractional advection-dispersion equation. The variation law of the result More >