W. M. Abd- Elhameed^1,2, Y. H. Youssri²

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.5, pp. 375-398, 2015, DOI:10.3970/cmes.2015.105.375

Abstract In this paper, a new spectral algorithm for solving linear and nonlinear fractional-order initial value problems is established. The key idea for obtaining the suggested spectral numerical solutions for these equations is actually based on utilizing the ultraspherical wavelets along with applying the collocation method to reduce the fractional differential equation with its initial conditions into a system of linear or nonlinear algebraic equations in the unknown expansion coefficients. The convergence and error analysis of the suggested ultraspherical wavelets expansion are carefully discussed. For the sake of testing the proposed algorithm, some numerical examples are More >

V. Giusti ¹, B. Montagnini ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.3, pp. 229-255, 2014, DOI:10.3970/cmes.2014.102.229

Abstract An application of a 3D Boundary Element Method (BEM), coupled with the Response Matrix (RM) technique, to solve the neutron diffusion and transport equations for multi-region domains is presented. The discussion is here limited to steady state problems, in which the neutrons have a wide energy spectrum, which leads to systems of several diffusion or transport equations. Moreover, the number of regions with different physical constants can be very large. The boundary integral equations concerning each region are solved via a polynomial moment expansion and, taking advantage of suitable recurrence formulas, the multi-fold integrals there… More >

ShiXu Guo¹, Shili Chen¹, Xinjing Huang¹, Yu Zhang¹, Shijiu Jin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.1, pp. 59-80, 2014, DOI:10.3970/cmes.2014.101.059

Abstract Spherical leak detectors can detect very tiny leakage in pipelines and have low risk of blockage. In this paper the passing ability of the detector in the vertical segment of a pipe was studied using CFD simulations and experiments. The Reynolds number for the sphere exceeds 10⁴ at the economical velocity range for oil pipelines, and there were few researches related to the hydrodynamic force on the sphere by the pipe flow at high Reynolds number. For sphere with different sizes and density, and at different flow rates, more than 100 3-D steady numerical simulations were… More >

Tai C. Lee¹, Huan J. Keh²

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.5, pp. 317-333, 2013, DOI:10.3970/cmes.2013.093.317

Abstract A theoretical study of the thermocapillary migration of a fluid sphere located at an arbitrary position inside a spherical cavity is presented in the quasisteady limit of small Reynolds and Marangoni numbers. The applied temperature gradient is perpendicular to the line through the drop and cavity centers. The general solutions to the energy and momentum equations governing the system are constructed from the superposition of their fundamental solutions in the spherical coordinates originating from the two centers, and the boundary conditions are satisfied by a multipole collocation method. Results for the thermocapillary migration velocity of… More >

Milind S. Patil^a,*, Ramchandra S. Jahagirdar^b, Eknath R. Deore^a,†

Frontiers in Heat and Mass Transfer, Vol.3, No.3, pp. 1-5, 2012, DOI:10.5098/hmt.v3.3.3008

Abstract Convection heat loss inevitably occurs in receivers of high concentrating solar concentrators. All the concentrators are need to be tack during the operation and hence the position of the receiver is changing continually. The angle of the receiver axis will then play an important role in the heat loss. Few researches were reported for the hemispherical cavity receivers numerically. The paper presented here is an experimental investigation natural convection heat loss from hemispherical cavity receiver. Cavity receiver of diameter 540 mm was tested. It is observed that the heat loss was minimum for 90° and More >

L. Dong¹, S. N. Atluri¹

CMC-Computers, Materials & Continua, Vol.29, No.2, pp. 169-212, 2012, DOI:10.3970/cmc.2012.029.169

Abstract In this paper, three-dimensionalT-Trefftz Voronoi Cell Finite Elements (VCFEM-TTs) are developed for micromechanical modeling of heterogeneous materials. Several types of VCFEMs are developed, depending on the types of heterogeneity in each element. Each VCFEM can include alternatively a spherical void, a spherical elastic inclusion, a spherical rigid inclusion, or no voids/inclusions at all.In all of these cases, an inter-element compatible displacement field is assumed at each surface of the polyhedral element, with Barycentric coordinates as nodal shape functions.The T-Trefftz trial displacement fields in each element are expressed in terms of the Papkovich-Neuber solution. Spherical harmonics… More >

V.A. Buryachenko^1,2, T.L. Jackson^2,3, G. Amadio³

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.5, pp. 379-416, 2012, DOI:10.3970/cmes.2012.085.379

Abstract We consider a composite medium, which consists of a homogeneous matrix containing a statistically homogeneous set of multimodal spherical inclusions. This model is used to represent the morphology of heterogeneous solid propellants (HSP) that are widely used in the rocket industry. The Lubachevsky-Stillinger algorithm is used to generate morphological models of HSP with large polydisperse packs of spherical inclusions. We modify the algorithm by proposing a random shaking procedure that leads to the stabilization of a statistical distribution of the simulated structure that is homogeneous, highly mixed, and protocol independent (in sense that the statistical More >

Du Qinghai, Cui Weicheng, Wang Yongjun

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.3, pp. 79-80, 2011, DOI:10.3970/icces.2011.019.079

Abstract The spherical shell is a typical form of revolution shells, which is widely used in pressure vessel and piping industry, nuclear power industry and ocean engineering for its specific structural shape to obtain kinds of performance. However compared to the cylindrical or conical shell, the spherical shell is mainly used as main structure or pressure hull in underwater engineering because of the superiority of theoretical solution and its manufacture. For the significance of the spherical shell, many researchers in the region of engineering and mechanics have spent great efforts to solve it and do lots… More >

Yan-ping CAO, Xiu-qing Qian, Norbert Huber

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.1, pp. 17-18, 2011, DOI:10.3970/icces.2011.019.017

Abstract In the development of a systematic method to determine the mechanical properties of materials using depth-sensing instrumented indentation tests, a key issue is to find the connection between the indentation response and the properties of the indented material. For spherical indentation into power law engineering materials, we showed that this problem can be solved by using the concept of the representative strain. In the present research, using finite element analysis based on the incremental plasticity theory and large deformation formulations, we proposed four indentationresponse based definitions of the representative strain. Each of them leads to… More >

Chikit Au¹, Yiyu Cai², Jianmin Zheng³, Tony Woo⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.68, No.3, pp. 221-238, 2010, DOI:10.3970/cmes.2010.068.221

Abstract A protein model (such as a ribbon model) can be created from the atomic coordinates in the protein data base files. These coordinates are obtained by X-ray crystallography or NMR spectroscopy with the protein arbitrarily oriented. As such, identifying or comparing a novel structure with a known item using protein model in the protein data base can be a timely process since a large number of transformations may be involved. The identification efficiency will be improved if the protein models are uniformly oriented. This paper presents an approach to orient a protein model to generate More >