Showing papers by "Ali J. Chamkha published in 2007"
TL;DR: In this article, the authors focused on the numerical study of steady, laminar, conjugate natural convection in a square enclosure with an inclined thin fin of arbitrary length.
126 citations
TL;DR: In this article, the steady laminar thermosolutal Marangoni convection in the presence of temperature-dependent volumetric heat sources/sinks as well as of a first-order chemical reaction is considered.
Abstract: The steady laminar thermosolutal Marangoni convection in the presence of temperature-dependent volumetric heat sources/sinks as well as of a first-order chemical reaction is considered in this paper. Assuming that the surface tension varies linearly with temperature and concentration and that the interface temperature and concentration are quadratic functions of the interface arc length x, exact analytical similarity solutions are obtained for the velocity, temperature and concentration fields. The features of these exact solutions as functions of the physical parameters of the problem are discussed in detail.
63 citations
TL;DR: In this paper, the authors focused on the numerical study of steady, laminar, conjugate natural convection around a finned pipe placed in the center of a square enclosure with uniform internal heat generation.
48 citations
TL;DR: In this article, the authors considered the problem of steady two-dimensional flow of a micropolar fluid impinging obliquely on a flat plate, which occurs in the boundary layer near an orthogonal stagnation point.
41 citations
TL;DR: In this article, the authors considered a non-Newtonian power-law fluid from a vertical plate embedded in a fluid-saturated porous medium in the presence of suction or injection and heat generation or absorption effects.
Abstract: – To consider simultaneous heat and mass transfer by mixed convection for a non‐Newtonian power‐law fluid from a permeable vertical plate embedded in a fluid‐saturated porous medium in the presence of suction or injection and heat generation or absorption effects., – The problem is formulated in terms of non‐similar equations. These equations are solved numerically by an efficient implicit, iterative, finite‐difference method., – It was found that as the buoyancy ratio was increased, both the local Nusselt and Sherwood numbers increased in the whole range of free and mixed convection regime while they remained constant for the forced‐convection regime. However, they decreased and then increased forming dips as the mixed‐convection parameter was increased from the free‐convection limit to the forced‐convection limit for both Newtonian and dilatant fluid situations., – The problem is limited to slow flow of non‐Newtonian power‐law fluids in porous media. Future research may consider inertia effects of porous media for relatively higher velocity flows., – A very useful source of information for researchers on the subject of non‐Newtonian fluids in porous media., – This paper illustrates simultaneous heat and mass transfer in porous media for power‐law fluids with heat generation or absorption effects.
31 citations
TL;DR: In this paper, a one-dimensional advective-dispersive contaminant transport model with scale-dependent dispersion coefficient in the presence of a nonlinea r chemical reaction of arbitrary order is considered.
Abstract: A one-dimensional advective-dispersive contaminant transport model with scale-dependent dispersion coefficient in the presence of a nonlinea r chemical reaction of arbitrary order is considered. Two types of variations of the dispersion coefficient with the downstream distance are considered. The first type assumes that the d ispersivity increases as a polynomial function with distance while the other assumes an exponentially- increasing function. Since the general problem is nonlinear and possesses no analytical solutions, a numerical solution based on an efficient implicit iterative tri-dia gonal finite- difference method is obtained. Comparisons with previously published analytical and numerical solutions for special cases of the main transport equation ar e performed and found to be in excellent agreement. A parametric study of all physical parameters is conducted and the results are presented graphically to illustrate interesting f eatures of the solutions. It is found that the chemical reaction order and rate coefficie nt have significant effects on the contaminant concentration profiles. Furthermore, the sc ale-dependent polynomial type dispersion coefficient is predicted to obtain significant ch anges in the contaminant concentration at all dimensionless time stages compared with the constant dispersion case. However, relatively smaller changes in the concentration level are predicted for the exponentially-increasing dispersion coefficient.
10 citations
TL;DR: In this paper, the dimensionless governing equations of the flow that are unsteady, coupled and non-linear partial differential equations are solved by an efficient, accurate and unconditionally stable finite difference scheme of Crank-Nicolson type.
Abstract: Natural convection effects of the numerical solution for unsteady, laminar, free convection flow over an incompressible viscous fluid past a no n-isothermal vertical cone with surface temperature T ' w(x) = T ' ∞ + ax n varying as power function of distance from the apex (x = 0) is presented here. The dimensionless governing equations of the flow that are unsteady, coupled and non-linear partial differential equations are solved by an efficient, accurate and unconditionally stable finite difference scheme of Crank-Nicolson type. The velocity and temperature fields ha ve been studied for various parameters Prandtl number, semi vertical angle 0 ◦ < � < 90 ◦ and n. The local as well as average skin-friction and Nusselt number are also presented and analyzed graphically. The present results are compared with available results in l iterature and are found to be in good agreement.
9 citations