Taoufik Naffouti^1,2 and Ridha Djebali^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.3, pp. 211-228, 2012, DOI:10.3970/cmes.2012.088.211

Abstract This paper reports numerical results of natural convection flow evolving inside confined medium defined by two-dimensional square enclosure containing isothermal hot source placed asymmetrically at bottom wall. The sides-walls are isothermally cooled at a constant temperature; however the ceiling and the rest of bottom wall are insulated. The lattice Boltzmann method is used to solve the dimensionless governing equations with the associated boundary conditions. The flow is monitored by the Grashof number and the Prandtl number taken here 0.71. Numerical simulations are performed to study the effects of Grashof number ranging from 104 to 106,… More >

Jiawei Xiang^1,2, Yanxue Wang³, Zhansi Jiang³, Jiangqi, Long¹, Guang Ma¹

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.1, pp. 1-16, 2012, DOI:10.3970/cmes.2012.088.001

Abstract Two-dimensional wavelet-based numerical approximation using Hermite cubic spline wavelet on the interval (HCSWI) is proposed to solve stress intensity factors (SIFs) of plate structures. The good localization property of wavelets is used to approximate displacement fields by multi-scale bases of HCSWI. Example computations are performed for plates with a central crack and double edge cracks. The numerical results prove that, compared with the conventional finite element method and the analytical solutions, the new procedure are efficient in both its accuracy and its reduction of degree of freedoms (DOFs). More >

W. A. El-Askary, A. Abdel-Fattah

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.4, pp. 425-458, 2012, DOI:10.3970/cmes.2012.083.425

Abstract In the present paper, experimental and numerical studies of heat transfer and the frictional head loss of turbulent flow in a duct with a heated upper surface are performed. Four different arrangements are considered (case 1: without baffles, case 2: one perforated baffle on the upper wall and one solid baffle on the lower wall, case 3: one perforated baffle on the upper wall and one perforated baffle on the lower wall and case 4: two perforated baffles on the upper wall). A numerical code developed by the present authors is simultaneously presented including four… More >

Li Shan, Ning Cui, Ming Cheng, Kaixin Liu

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.4, pp. 353-384, 2012, DOI:10.3970/cmes.2012.083.353

Abstract In the present paper, a combined scheme of discrete element method (DEM) and meshless method for numerical simulation of impact problems is proposed. Based on the basic principle of continuum mechanics, an axisymmetric DEM framework is established for modeling the elastoplastic behavior of solid materials. Failure criteria are introduced to model the transformation from a continuum to a discontinuum. The friction force between contact elements is also considered after the failure appears. So our scheme can calculate not only the behavior of continuum and discontinuum, but also the transformation process from a continuum to a More >

Walid Hassen¹, Mohamed Naceur Borjini², Habib Ben Aissia¹

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.4, pp. 381-396, 2012, DOI:10.3970/fdmp.2012.008.381

Abstract In this work we consider the problem related to the electro-thermo-convection of a dielectric fluid in a rectangular enclosure placed between two electrodes. This layer is subjected simultaneously to the injection of electric charges and to a thermal gradient. The influence of the electric Rayleigh number (200 - 1000) on the structure of the flow, the density of electric charge and heat transfer is investigated. An oscillatory flow is observed and discussed in detail. More >

F.Z. Ferahta^1,2, S. Bougoul¹, M. Médale², C. Abid²

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.3, pp. 339-352, 2012, DOI:10.3970/fdmp.2012.008.339

Abstract A numerical study is carried out to evaluate the thermal performances of a solar collector. As it is well known, that the thermal losses of such systems are mainly of a convective nature, the study is concentrated in particular on the features of natural convection that is activated in the air domain delimited by the upper glass and the lower absorber of the solar collector. The efficiency of such a system depends essentially on both the temperature difference and the distance between the absorber and the glass. Since the temperature difference remains an uncontrolled variable More >

Y. Amirouche¹, R. Bessaïh²

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.3, pp. 295-310, 2012, DOI:10.3970/fdmp.2012.008.295

Abstract This paper summarizes a series of computational results originating from the simulation of three-dimensional turbulent natural convection occurring in a vertical channel containing 5 cubic aluminum heated sources (mimicking a set of electronics components equally spaced in the vertical direction). A three-dimensional, conjugate heat transfer model with appropriate boundary conditions is used. In particular, the governing equations are solved by a finite volume method throughout the entire physical domain. Calculations are made for distinct values of: the Rayleigh number, the ratio (air/solid) of thermal conductivities and other geometrical parameters (in order to examine the influence More >

A. Saad^1,2, A. Echchelh¹, M. Hattabi³, M. El Ganaoui⁴, F. Lahlou¹

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.3, pp. 277-294, 2012, DOI:10.3970/fdmp.2012.008.277

Abstract A modified finite element/control volume (FE/CV) method is used to solve the resin flow problem. Full advantage is taken of some of the intrinsic peculiar characteristics of the method, in particular, of its capability of eliminating the need to remesh continuously the resin-filled domain at each time step. The model leads to the numerical prediction of temperature, pressure distribution and flow front position with great accuracy, together with a precise representation of the thermal (spatio-temporal) behaviour of the resin inside the mould. The validity of such approach is validated by comparison with available analytical results. More >

A. Arid¹, T. Kousksou¹, S.Jegadheeswaran², A. Jamil³, Y. Zeraouli¹

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.3, pp. 257-276, 2012, DOI:10.3970/fdmp.2012.008.257

Abstract A two-dimensional numerical model has been developed to investigate the phase-change of ice near 4 °C in a rectangular cavity. The enthalpy-porosity model is reformulated in terms of conservation equations of mass, momentum and heat to account for the evolution the solid/liquid interface. Constant and time-dependent (with sinusoidal law) temperature boundary conditions are considered. Results confirm the possibility to control the typical dynamics of ice melting in a square cavity near the density inversion point by means of a wall temperature which varies in time (with given amplitude and frequency). More >

Pankaj Saha^a, Gautam Biswas^a,b,*

Frontiers in Heat and Mass Transfer, Vol.2, No.3, pp. 1-5, 2011, DOI:10.5098/hmt.v2.3.3008

Abstract Detailed flow structure in turbulent flows through a rectangular channel containing built-in winglet type vortex generators have been analyzed by means of solutions of the full Navier-Stokes equations using a Large-Eddy Simulation (LES) technique. The Reynolds number of investigation is 6000. The geometry of interest consists of a rectangular channel with a built-in winglet pair on the bottom wall with common-flow-down arrangement. The winglet pair induces streamwise longitudinal vortices behind it. The vortices swirl the flow around the axis parallel to the mainstream direction and disrupt the growth of thermal boundary layer entailing enhancement of… More >