G. Kosec¹, B. Šarler²

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.2, pp. 191-216, 2009, DOI:10.3970/cmes.2009.047.191

Abstract This paper explores an application of a novel mesh-free Local Radial Basis Function Collocation Method (LRBFCM) [Sarler and Vertnik (2006)] in solution of coupled heat transfer and fluid flow problems with solid-liquid phase change. The melting/freezing of a pure substance is solved in primitive variables on a fixed grid with convection suppression, proportional to the amount of the solid fraction. The involved temperature, velocity and pressure fields are represented on overlapping sub-domains through collocation by using multiquadrics Radial Basis Functions (RBF). The involved first and second derivatives of the fields are calculated from the respective derivatives of the RBF's. The… More >

Raquel R. Pinho¹, João Manuel R. S. Tavares¹

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.1, pp. 51-76, 2009, DOI:10.3970/cmes.2009.046.051

Abstract This work addresses the problem of tracking feature points along image sequences. In order to analyze the undergoing movement, an approach based on the Kalman filtering technique has been used, which basically carries out the estimation and correction of the features' movement in every image frame. So as to integrate the measurements obtained from each image into the Kalman filter, a data optimization process has been adopted to achieve the best global correspondence set. The proposed criterion minimizes the cost of global matching, which is based on the Mahalanobis distance. A management model is employed to manage the features being… More >

Chia-Yi Cheng, Cha’o-Kuang Chen¹, Yue-Tzu Yang

CMES-Computer Modeling in Engineering & Sciences, Vol.44, No.3, pp. 203-218, 2009, DOI:10.3970/cmes.2009.044.203

Abstract This paper seeks to utilize the residual correction method in coordination with the evolutionary monotonic iteration technique to obtain upper and lower approximate solutions of non-linear heat transfer problem of the annular hyperbolic profile fins whose thermal conductivity vary with temperature. First, the monotonicity of a non-linear differential equation is reinforced by using the monotone iterative technique. Then, the cubic spline method is applied to discretize and convert the differential equation into the mathematical programming problems. Finally, based on the residual correction concept, the complicated constraint inequality equations can be transferred into the simple iterative equations. As verified by this… More >

Rencheng Song^1,2, Wen Chen^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.42, No.1, pp. 59-70, 2009, DOI:10.3970/cmes.2009.042.059

Abstract The regularized meshless method (RMM) is a novel boundary-type meshless method but by now has mainly been tested successfully to the regular domain problems in reports. This note makes a further investigation on its solution of irregular domain problems. We find that the method fails to produce satisfactory results for some benchmark problems. The reason is due to the inaccurate calculation of the diagonal elements of the numerical discretization matrix in the original RMM, which have strong effect on the resulting solution accuracy. To overcome this severe drawback, this study introduces the weighted diagonal element approach. Our numerical experiments demonstrate… More >

N.B.Petrovskaya ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.32, No.2, pp. 69-84, 2008, DOI:10.3970/cmes.2008.032.069

Abstract Discontinuous weighted least--squares (DWLS) approximation is a modification of a standard weighted least-squares approach that nowadays is intensively exploited in computational aerodynamics. A DWLS method is often employed to approximate a solution function over an unstructured computational grid that results in an irregular local support for the approximation. While the properties of a weighted least-squares reconstruction are well known for regular geometries, the approximation over a non-uniform grid is not a well researched area so far. In our paper we demonstrate the difficulties related to the performance of a DWLS method on distorted grids and outline a new approach based… More >

L. Codecasa¹, R. Specogna², F. Trevisan³

CMES-Computer Modeling in Engineering & Sciences, Vol.31, No.3, pp. 129-144, 2008, DOI:10.3970/cmes.2008.031.129

Abstract In the paper we introduce a methodology to construct discrete constitutive matrices relating magnetic fluxes with magneto motive forces (reluctance matrix) and electro motive forces with currents (conductance matrix) needed for discretizing eddy current problems over hexahedral primal grids by means of the Finite Integration Technique (FIT) and the Cell Method (CM). We prove that, unlike the mass matrices of Finite Elements, the proposed matrices ensure both the stability and the consistency of the discrete equations introduced in FIT and CM. More >

Ömer Civalek ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.31, No.1, pp. 25-36, 2008, DOI:10.3970/cmes.2008.031.025

Abstract In this paper, free vibration analysis of curvilinear or straight-sided quadrilateral membranes is presented. In the proposed approach, irregular physical domain is transformed into a rectangular domain by using geometric coordinate transformation. For demonstration of the accuracy and convergence of the method, some numerical examples are provided on membranes with different geometry such as skew, trapezoidal, sectorial, annular sectorial, and membranes with four curved edges. The results obtained by the DSC method are compared with those obtained by other numerical and analytical methods. More >

H.M. Lee¹, H.S. Park^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.29, No.1, pp. 29-44, 2008, DOI:10.3970/cmes.2008.029.029

Abstract This paper presents a computational model to estimate deformed shapes of beam structures using 3D coordinate information from terrestrial laser scanning (TLS). The model is composed of five components: 1) formulation of polynomial shape function, 2) application of boundary condition, 3) inducement of compatibility condition, 4) application of the least square method and 5) evaluation of error vector and determination of reasonable polynomial shape function. In the proposed model, the optimal degree of polynomial function is selected based on the complexity of beam structures, instead of using a specific degree of polynomial function. The chosen polynomial function for estimation is… More >

K. Han ¹, Y. T. Feng ¹, D. R. J. Owen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.2, pp. 87-100, 2007, DOI:10.3970/cmes.2007.018.087

Abstract Numerical procedures are introduced for simulations of irregular particle transport in turbulent flows using the coupled lattice Boltzmann method (LBM) and the discrete element method (DEM). The fluid field is solved by the extended LBM with the incorporation of the Smagorinsky turbulence approach, while particle interaction is modeled by the DEM. The hydrodynamic interactions between fluid and particles are realised through an immersed boundary condition, which gives rise to a coupled solution strategy to model the fluid-particle system under consideration. Main computational aspects comprise the lattice Boltzmann formulation for the solution of fluid flows; the incorporation of the large eddy… More >

B. F. Romanowicz¹, M. H. Zaman¹, S. F. Bart¹, V. L. Rabinovich¹, I. Tchertkov¹, S. Zhang¹, M. G. da Silva¹, M. Deshpande¹, K. Greiner¹, J. R. Gilbert¹, Shawn Cunningham²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 45-64, 2000, DOI:10.3970/cmes.2000.001.045

Abstract Development of micro-electro-mechanical systems (MEMS) products is currently hampered by the need for design aids, which can assist in integration of all domains of the design. The cross-disciplinary character of microsystems requires a top-down approach to system design which, in turn, requires designers from many areas to work together in order to understand the effects of one sub-system on another. This paper describes current research on a methodology and tool-set which directly support such an integrated design process. More >