Mounir Kriraa^1,2,*, Khalid Souhar³, Driss Achemlal⁴, Youssef Ait Yassine^5,6, Abdelmajid Farchi¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.2, pp. 199-209, 2020, DOI:10.32604/fdmp.2020.07986

Abstract In this paper, a detailed investigation of water (Pr ¼ 7:0) convection in a chemical condenser is carried out. Two openings are located along one side of the cavity. The Navier-Stokes equations are solved in the frame of a control volume method using the SIMPLEC algorithm to implement adequate coupling of pressure and velocity. Special emphasis is given to the influence of the Reynolds number, the tilt of the channel and the Rayleigh number on the convective heat transfer. Results are presented and discussed allowing the control parameters to span relatively wide intervals: Rayleigh number (10⁴ ≤ Ra ≤ 5… More >

Primož Kocutar^{1, *}, Jure Ravnik¹, Leopold Škerget¹

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 1-22, 2020, DOI:10.32604/cmes.2020.08728

Abstract In this paper, we develop and test a unified hybrid LES/URANS turbulence model with two different Large Eddy Simulation (LES) turbulence models. The numerical algorithm is based on the Boundary Element Method. In the existing hybrid LES/URANS turbulence model we implemented a new Smagorinsky LES turbulence model. The hybrid LES/URANS turbulence model is unified, which means that the LES/URANS interface is changed dynamically during simulation using a physical quantity. In order to define the interface between LES and unsteady Reynolds Averaged Navier Stokes (URANS) zones during the simulation, we use the Reynolds number based on turbulent kinetic energy as a… More >

Suvash C. Saha^1,*, Ali M. Sefidan², Atta Sojoudi³

Energy Engineering, Vol.117, No.1, pp. 1-17, 2020, DOI:10.32604/EE.2020.010418

Abstract Free convection inside an attic enclosure in which sinusoidal heat flux applied on the inclined walls and a constant temperature applied on the base wall has been investigated numerically to demonstrate the primary flow characteristics and heat transfer within the attic enclosure over daily routine cycles. To solve the governing equations, the finite volume technique has been utilized. After performing the grid independency and time step size tests, the roles of Rayleigh number (Ra) and the attic aspect ratio (AR) on the unsteady flow structure and heat transfer phenomenon are explained for a constant Prandtl number (0.72) for the air.… More >

Mohamed Abd El-Aziz^{1, 2}, A. M. Aly^{1, 3, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 525-549, 2020, DOI:10.32604/cmc.2020.08576

Abstract This study focusses on the numerical investigations of boundary layer flow for magnetohydrodynamic (MHD) and a power-law nanofluid containing gyrotactic microorganisms on an exponentially stretching surface with zero nanoparticle mass flux and convective heating. The nonlinear system of the governing equations is transformed and solved by Runge-Kutta-Fehlberg method. The impacts of the transverse magnetic field, bioconvection parameters, Lewis number, nanofluid parameters, Prandtl number and power-law index on the velocity, temperature, nanoparticle volume fraction, density of motile microorganism profiles is explored. In addition, the impacts of these parameters on local skin-friction coefficient, local Nusselt, local Sherwood numbers and local density number… More >

Y.R. Li¹, L. Peng¹, W.Y. Shi¹, N. Imaishi²

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 153-166, 2006, DOI:10.3970/fdmp.2006.002.153

Abstract The convective instabilities in semiconduc-tor or oxide melts, significantly affect the quality oflarge crystals grown from the melts by the Czochralskimethod. This paper reviewsour recent numerical stud-ies of thermal convection in annular pools of low-Pr sili-con melt and moderate-Pr silicone oil. The mechanismsof the convective instability are discussed and the criticalconditions for the onset of three-dimensional flow are de-termined. The results show that the hydrothermal wave,characterized by curved spokes, is dominant in a shallowthin pool. In a thick pool of the low-Pr silicon melt, thereappears a standing wave type of oscillatory longitudinalrolls, which moves in the azimuthal direction and looksvery… More >

A. Ja¹, A. Cheddadi¹

FDMP-Fluid Dynamics & Materials Processing, Vol.13, No.4, pp. 235-249, 2017, DOI:10.3970/fdmp.2017.013.235

Abstract This paper reports on the natural convection within a very narrow horizontal annular cavity filled with a porous medium saturated by a binary fluid. The main objective of this study is the identification of the effect of Lewis number on the flow structure and on the heat and mass transfer rates, in a cavity of very small radius ratio R=1.05, in the case of equal buoyancy forces (N=1), for a Rayleigh number Ra=50. The dimensionless governing equations were solved by the centered Finite Difference method using the ADI scheme. Several multicellular flows appear during the variation of the Lewis number,… More >

Hiromoto Susawa

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.1, pp. 15-16, 2011, DOI:10.3970/icces.2011.017.015

Abstract Liquid Phase Epitaxy is a crystal growth on a substrate from liquid solution, which is a melt in this paper. Before growth, a melt is separated from a substrate and supercooled. When growth starts, the melt moves to the substrate. This induces flow in the melt. This paper considers the influence of flow on the composition of solid phase, reviews previous simulation models and introduces a new model. A one-dimensional model explained an experimental result and a major behavior of solid compositional variation. A semi-two-dimensional (semi-2-D) model dealt with transport in the melt as 2-D but substituted the values at… More >

Janja Kramer, Renata Jecl, Leopold Skerget

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.4, pp. 147-148, 2009, DOI:10.3970/icces.2009.012.147

Abstract A numerical study of double diffusive natural convection in porous media due to opposing buoyancy forces is reported, using the Boundary Domain Integral Method (BDIM). There have been several reported studies dealing with natural convection in porous media, mainly because of its importance in several industrial and technological applications. Less attention, however, has been dedicated to the so-called double diffusive problems, where density gradients occur due to the effects of combined temperature and concentration buoyancy. The current investigation is focused on the special problem, where the thermal and solutal buoyancy forces are opposing each other.
The mathematical model of fluid… More >

Kai-Long Hsiao¹, Cheng-Hsing Hsu²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.1, pp. 3-22, 2009, DOI:10.3970/icces.2009.009.003

Abstract A conjugate forced convection with viscous dissipation heat transfer problem of a second-grade visco-elastic fluid past a flat plate fin has been studied. Governing equations include heat conduction equation of the fin, and continuity equation, momentum equation and energy equation of the fluid, were analyzed by a combination of a series expansion method, the similarity transformation and a second-order accurate finite-difference method. Solutions of a stagnation flow (β = 1.0) at the fin tip and a flat plate shape (wedge flow β = 0.0) on the fin surface were obtained by a generalized Falkner-Skan flow derivation. These solutions were used… More >

N. Simões^1,2, A. Tadeu²

CMES-Computer Modeling in Engineering & Sciences, Vol.9, No.3, pp. 221-234, 2005, DOI:10.3970/cmes.2005.009.221

Abstract The use of the Boundary Element Method (BEM) to formulate the 3D transient heat transfer through cylindrical structures with irregular cross-sections, bounded by a homogeneous elastic medium, is described in this paper. In this formulation, both the conduction and the convection phenomena are modeled. This system can be subjected to heat emitted by either point or line sources located somewhere in the media. The solution is first obtained in the frequency domain for a wide range of frequencies and axial wavenumbers. Time domain responses are later calculated by means of (fast) inverse Fourier transforms into space-time. The appropriate fundamental solution… More >