Open Access
ARTICLE
Huamin Zhou1, Hua Zhang, Dequn Li2
CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 209-220, 2009, DOI:10.3970/cmes.2009.046.209
Abstract Gas-assisted injection molding is an innovative process to manufacture hollow polymeric products, in which gas penetration is the primary and key problem. An analytical solution of the gas penetration interface is presented, based on perturbation method. First, the governing equations and boundary conditions are transformed to be dimensionless, where Capillary number Ca is introduced. Then matching asymptotic expansion method is applied to solve these equations, by using Ca and as perturbation parameters to get the inner and outer solutions, respectively. By matching these two solutions, the analytical model of gas penetration is obtained. More >
Open Access
ARTICLE
Liviu Marin1
CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 221-254, 2009, DOI:10.3970/cmes.2009.046.221
Abstract We investigate the stable numerical reconstruction of an unknown portion of the boundary of a two-dimensional domain occupied by a functionally graded material (FGM) from a given boundary condition on this part of the boundary and additional Cauchy data on the remaining known portion of the boundary. The aforementioned inverse geometric problem is approached using the method of fundamental solutions (MFS), in conjunction with the Tikhonov regularization method. The optimal value of the regularization parameter is chosen according to Hansen's L-curve criterion. Various examples are considered in order to show that the proposed method is numerically stable with respect to… More >
Open Access
ARTICLE
T.N. Killian1, S.M. Rao1 and M.E. Baginski1
CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 255-270, 2009, DOI:10.3970/cmes.2009.046.255
Abstract In this work, we present a new method of moments solution procedure for calculating acoustic/electromagnetic scattering and radiation by a metallic body whose physical dimension is very large with respect to wavelength. The specially computed basis functions and the testing procedure results in a block-diagonally-dominant moment matrix where each block along the diagonal corresponds to a portion of the structure. The new solution procedure results in considerable savings in terms of computer storage and processing times. Although the procedure is outlined in general mathematical terms, the numerical results are presented only for electromagnetic scattering from two-dimensional bodies and compared with… More >
Open Access
ARTICLE
Xie Ming-Liang1,2, Zhou Huai-Chun1, Chan Tat-Leung3
CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 271-290, 2009, DOI:10.3970/cmes.2009.046.271
Abstract A Fourier-Chebyshev Petrov-Galerkin spectral method is described for computation of temporal linear stability in a circular jet. Basis functions presented here are exponentially mapped Chebyshev functions. They satisfy the pole condition exactly at the origin, and can be used to expand vector functions efficiently by using the solenoidal condition. The mathematical formulation is presented in detail focusing on the analyticity of solenoidal vector field used for the approximation of the flow. The scheme provides spectral accuracy in the present cases studied and the numerical results are in agreement with former works. More >