Yongsheng An¹, Xiaodong Wu¹, Deli Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 123-142, 2012, DOI:10.3970/cmes.2012.089.123

Abstract The accuracy of numerical simulation of a two-phase (oil and water) flow in a fractured horizontal well depends greatly upon the types of grids used in the computation. Cartesian grids have been widely used in recent years, but they have some disadvantages in describing complex structural wells, such as fractured horizontal wells. For example, Cartesian grids are not efficient in describing the main wellbores and the fractures of fractured horizontal wells, and the results can frequently suffer from grid orientation effects, even though a grid-refinement is often introduced to enhance the adaptability of a Cartesian grid. The PEBI (Perpendicular Bisector)… More >

Fei Yin¹, Deli Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.1, pp. 25-38, 2012, DOI:10.3970/cmes.2012.089.025

Abstract The methods to design the casings used in oilfields, are currently based on the assumptions that the remote crustal-stress-field is axially symmetric, in plane strain. However, most of the failures of the casings are caused by non-uniform and asymmetric far-field crustal stresses, so that it is necessary for a proper design of the casings, to investigate and understand the casing's behavior under non-uniform far-field crustal stresses. A mechanical model is first established for the system, consisting of the casing and formation, by using the plane strain theory of linear elasticity. The non-uniform crustal stress is resolved into a uniform stress… More >

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, hot source length from 0.1… 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 >

Qiang Li, Jie Ouyang¹, Xuejuan Li², Guorong Wu², Binxin Yang²

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 247-268, 2011, DOI:10.3970/cmes.2011.074.247

Abstract A unified mathematical model is proposed to predict the short shot, primary and secondary gas penetration phenomenon in gas-assisted injection molding (GAIM) process, where the Cross-WLF model and two-domain modified Tait equation are employed to simulate the melt viscosity and density in the whole process, respectively. The governing equations of two-phase flows including gas, air and polymer melt are solved using finite volume method with SIMPLEC technology. At first, two kinds of U-shaped gas channels are modeled, where the shape corner and generous corner cases are studied. At last, as a case study, the short shot, primary and secondary gas… More >

H. T. Wang, G. Hall, S. Y. Yu, Z. H. Yao

CMES-Computer Modeling in Engineering & Sciences, Vol.37, No.2, pp. 153-174, 2008, DOI:10.3970/cmes.2008.037.153

Abstract Graphite materials are widely used in gas-cooled nuclear reactors as both moderators and reflectors. The graphite properties change when the microstructure damage occurs due to the in-core radiation and oxidation, thereby having a strong impact on the service life of graphite. In this paper, the X-ray tomography and the boundary element method (BEM) are introduced to the microstructure modeling and numerical simulations of both the mechanical and thermal property changes of nuclear graphite due to radiolytic oxidation. The model is established by the three-dimensional X-ray scan on the isotropic nuclear graphite Gilsocarbon, which is used in the UK commercial reactors.… More >

H. Kawai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.11, No.3, pp. 111-120, 2006, DOI:10.3970/cmes.2006.011.111

Abstract ADVENTURE AutoGL (pronounced as ‘Ote- ga-lu’) is a graphics and GUI library, dedicated for simulation-based research and development. It is designed for the simulation users to develop their own data viewers and editors. Currently, the library is used among many researchers and simulation users, mainly in universities and national research centers. Its functionalities and supported platforms are explained. AutoGL applications of various kinds of simulation methods are demonstrated also. More >

Banghua Yao^1,2, Jianping Wei¹, Dengke Wang¹, Dan Ma^2,3, Zhanqing Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.2, pp. 81-100, 2013, DOI:10.3970/cmes.2013.091.081

Abstract Presently, there is an increasing number of water outburst accidents in China as mining activity continues to develop to deeper ground. In these accidents, water outburst caused by karst collapse columns often results in serious damage, involving both the loss of lives and significant economic loss. Therefore, it is of utmost importance to study the seepage property and water outburst mechanism of karst collapse columns. In this paper, based on the seepage theory and the groundwater dynamic theory of porous media, a fluid-solid coupling model for karst collapse columns was built and then imported into COMSOL Multiphysics to be solved,… 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 different turbulence models; namely: the… 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 discontinuum. In addition, a meshless… More >