Marcello Lappa^{1, 2}

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.1, pp. 1-20, 2005, DOI:10.3970/fdmp.2005.001.001

Abstract Possible natural transport mechanisms in cubical and shallow cavities with different heating conditions (from below or from the side) are investigated by means of numerical solution of the non-linear model equations and multiprocessor computations. Attention is focused on a variety of three-dimensional steady effects that can arise in such configurations in the case of low-Pr liquids (silicon melt) even for relatively small values of the temperature gradient due to localized boundary effects and/or true instabilities of the flow. Such aspects are still poorly known or completely ignored owing to the fact that most of the More >

Alvaro Valencia¹

Molecular & Cellular Biomechanics, Vol.1, No.3, pp. 221-232, 2004, DOI:10.3970/mcb.2004.001.221

Abstract Flow dynamics play an important role in the pathogenesis and treatment of intracranial aneurysms. The evaluation of the velocity field in the aneurysm dome and neck is important for the correct placement of endovascular coils, and the temporal and spatial variations of wall shear stress in the aneurysm are correlated with its growth and rupture. This numerical investigation describes the hemodynamic in two models of terminal aneurysm of the basilar artery. Aneurysm models with a aspect ratio of 1.0 and 1.67 were studied. Each model was subject to physiological representative waveform of inflow for a More >

H.S. Wijesinghe¹, N.G. Hadjiconstantinou²

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.6, pp. 515-526, 2004, DOI:10.3970/cmes.2004.005.515

Abstract We present an implicit hybrid atomisticcontinuum formulation for unsteady, viscous, incompressible flows. The coupling procedure is derived from a domain decomposition method known as the Schwarz alternating method. A dilute gas impulsive Couette flow test problem is used to verify the hybridscheme. Finally, a method to reduce computational costs through limited ensemble averaging is presented. The implicit formulation proposed here is expected to be significantly faster than a time explicit approach based on a compressible formulation for the simulation of low speed flows such as those found in micro- and nano–scale devices. More >

Rosario M. A. Marretta¹, Giovanni Lombardi², Roberto Antinoro¹

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.1, pp. 73-84, 2003, DOI:10.3970/cmes.2003.004.073

Abstract An approach based on Lighthill's transpiration velocity is explored and proposed for a new design criterion for airfoils in unsteady and viscous flows. This criterion confines its methodologies to the close proximity of the laminar and turbulent boundary layer and it shows good efficiency in predicting and calculating the wake evolution regions in a wide range of operating unsteady parameters. Also, the criterion is capable of predicting low Mach number, attached flow-fields as accurately as the full Navier-Stokes solutions when the massive flow separation is avoided. The agreement of the present results with those empirically More >

Michael J. Rodgers¹, Leon M. Keer, Herbert S. Cheng

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 483-496, 2002, DOI:10.3970/cmes.2002.003.483

Abstract The steady-state temperature rise due to frictional heating on the surface of coated halfspaces and halfplanes is described by closed form expressions in the Fourier transformed frequency domain. These frequency response functions (FRFs) include the effects of the coating and the speed of the moving heat source and apply for all Peclet number regimes. Analytical inversion of these expressions for several special cases shows the Green's functions as infinite series of images, which may be costly and slowly convergent. Also, the influence coefficients integrated from these Green's functions are not available in closed form. Applying… More >

Y. Ochiai

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 435-446, 2001, DOI:10.3970/cmes.2001.002.435

Abstract The boundary element method (BEM) is useful in solving the steady heat conduction problem of orthotropic bodies without heat generation. However, for cases with arbitrary heat generation, a number of internal cells are necessary. In this paper, it is shown that the problem of steady heat conduction in orthotropic bodies with heat generation can be solved without internal cells by the triple-reciprocity BEM. In this method, the distribution of heat generation is interpolated using integral equations. In order to solve the problem, the values of heat generation at internal points and on the boundary are More >

Haruhiko Kohno, Takahiko Tanahashi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.2, pp. 155-170, 2001, DOI:10.3970/cmes.2001.002.155

Abstract Three-dimensional (3D) unsteady numerical simulations are carried out by means of the finite element method (FEM) with the generalized simplified marker and cell (GSMAC) method in silicon melt with a non-deformable free surface with Prandtl number Pr = 1.8534 × 10^-2, Marangoni number Ma = 0.0 - 6.2067 × 10², Grashof number Gr = 7.1104 × 10⁶, and the aspect ratio As = 1.0 in the Czochralski (CZ) method. The flow state becomes unstable earlier by increasing the absolute value of the thermal coefficient of surface tension in the range of σ_T =0.0 - 1.5 × 10^-5N/mK. Although… More >

N.S. Mera, L. Elliott, D.B. Ingham, D. Lesnic¹

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 101-106, 2000, DOI:10.3970/cmes.2000.001.403

Abstract In this paper the iterative algorithm proposed by [Kozlov and Maz'ya (1990)] for the backward heat conduction problem is extended in order to solve the Cauchy steady state heat conduction problem and the accuracy, convergence and stability of the numerical algorithm are investigated. The numerical results which are obtained confirm that this new iterative BEM procedure is accurate, convergent and stable with respect to increasing the number of boundary elements and decreasing the amount of noise which is added into the input data. More >