Radiation effect on mixed convection laminar flow along a vertical wavy surface (original) (raw)
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RADIATION EFFECT ON NATURAL CONVECTION LAMINAR FLOW ALONG A VERTICAL WAVY SURFACE
The effect of thermal radiation on a steady two-dimensional natural convection laminar flow of viscous incompressible optically thick fluid along a vertical wavy surface has been investigated. Using the appropriate variables; the basic equations are transformed into the local non-similarity boundary layer form and then solved employing the Keller-box scheme of finite difference method. Numerical results are presented by streamline, isotherms, velocity and temperature distribution of the fluid as well as the local heat transfer rate in terms of local Nusselt number and average rate of heat transfer for a wide range of Planck number R d and the surface heating parameter θ w . The present numerical result shows excellent agreement with the published results when the effect of thermal radiation was passed over.
The effect of thermal radiation on a steady two-dimensional natural convection laminar flow of viscous incompressible optically thick fluid along a vertical flat plate with streamwise sinusoidal surface temperature has been investigated in this study. Using the appropriate variables, the basic governing equations are transformed to convenient form and then solved numerically employing two efficient methods, namely, the Implicit Finite Difference method (IFD) together with the Keller box scheme and Straight Forward Finite Difference (SFFD) method. The effects of the variation of the physical parameters, for example, conduction–radiation parameter (Planck number), surface temperature parameter, and the amplitude of the surface temperature, are shown on the skin-friction. Heat transfer rate is shown quantitatively and numerically. Velocity and temperature profiles as well as streamlines and isotherms are also presented and discussed for the variation of the conduction–radiation parameter. It is found that both skin-friction and rate of heat transfer are enhanced considerably by increasing the values of conduction radiation parameter, Rd.
Effect of thermal radiation on free convection boundary layer flow over a vertical wavy cone
IOSR Journal of Applied Physics, 2013
Effect of thermal radiation on a steady two-dimensional free convection laminar boundary layer flow of a viscous incompressible optically thick fluid over a vertical wavy cone has been investigated. Using appropriate transformations, the basic governing equations are transformed into non-dimensional boundarylayer equations. These equations are then solved numerically by using Mathematica technique. The effect of the radiation parameter on velocity, temperature, skin friction and local Nusselt number has been discussed with graphical representation.
Radiation effect on natural convection boundary layer flow over a vertical wavy frustum of a cone
The effect of thermal radiation on a steady two-dimensional natural convection laminar boundary layer flow of a viscous incompressible optically thick fluid over a vertical wavy frustum of a cone has been investigated. The boundary layer regime when the Grashof number Gr is large is considered. Using appropriate transformations, the basic governing equations are transformed into a dimensionless form and then solved numerically employing two efficient methods, namely: (a) implicit finite difference method together with Keller-box scheme and (b) direct numerical scheme. Numerical results are presented by streamline, isotherms, velocity and temperature distribution of the fluid, as well as the local shearing stress in terms of the local skin-friction coefficient, the local heat transfer rate in terms of local Nusselt number, and the average rate of heat transfer for a wide range of the radiation–conduction parameter or Planck number Rd and the surface heating parameter θw.
Natural convection flow with surface radiation along a vertical wavy surface
Accepted in Numerical Heat Transfer: Part A
In this study, natural convection boundary layer flow of thermally radiating fluid along a heated vertical wavy surface is analyzed. Here the radiative component of heat flux emulates the surface temperature. Governing equations are reduced to dimensionless form subject to the appropriate transformation. Resulting dimensionless equations are transformed to a set of parabolic partial differential equations by using primitive variable formulation, which are then integrated numerically via iterative finite difference scheme. Emphasis has been given to low Prandtl number fluid. The numerical results obtained for the physical parameter, such as, surface radiation parameter, R, and radiative length parameter, ξ, are discussed in terms of local skin friction and Nusselt number coefficients. Comprehensive interpretation of velocity distribution is also given in the form of streamlines."
International Journal of Thermal Sciences, 2014
In this article, natural convection boundary layer flow is investigated over a semi-infinite horizontal wavy surface. Such an irregular (wavy) surface is used to exchange heat with an external radiating fluid which obeys Rosseland diffusion approximation. The boundary layer equations are cast into dimensionless form by introducing appropriate scaling. Primitive variable formulations (PVF) and stream function formulations (SFF) are independently used to transform the boundary layer equations into convenient form. The equations obtained from the former formulations are integrated numerically via implicit finite difference iterative scheme whereas equations obtained from lateral formulations are simulated through Keller-box scheme. To validate the results, solutions produced by above two methods are compared graphically. The main parameters: thermal radiation parameter and amplitude of the wavy surface are discussed categorically in terms of shear stress and rate of heat transfer. It is found that wavy surface increases heat transfer rate compared to the smooth wall. Thus optimum heat transfer is accomplished when irregular surface is considered. It is also established that high amplitude of the wavy surface in the boundary layer leads to separation of fluid from the plate.
The effect of viscous dissipation and heat absorption on a steady two-dimensional natural convection laminar flow of viscous incompressible fluid with uniform surface temperature along a vertical wavy surface has been investigated. Using the appropriate variables; the basic equations are transformed to convenient form and then solved numerically employing very efficient method, namely Keller-Box method (KBM). Numerical results are presented by the shearing stress in terms of the local skin-friction coefficient; the rate of heat transfer in terms of local Nusselt number, streamline and isotherms, respectively for a wide range of the viscous dissipation parameter N and heat absorption parameter Q. Increasing Q and lessening N cause the enhancement of heat transfer rate.
International Journal of Heat and Mass Transfer, 2015
Heat transfer by simultaneous radiation and natural convection through an optically thick fluid over a heated vertical plate has been studied with first-order momentum and thermal non-continuum boundary conditions. The radiant heat flux was treated using the Rosseland diffusion approximation. By solving the local non-similarity two-equation model, numerical solutions were obtained to examine the slip effects on the interaction between radiation and natural convection for a range of rarefied conditions and radiation effects. Results including slip velocity, temperature jump, skin friction, and heat transfer rate are presented graphically and discussed. In addition, an integral correlation is presented for the average Nusselt number as a function of the non-continuum conditions, radiation-conduction parameter, and flow properties.
The effect of radiation on mixed convection flow past a stretching surface
Heat and Mass Transfer, 2008
A boundary layer analysis is presented for a study of the influence of radiation and buoyancy on heat and mass transfer characteristics of continuous surfaces having a prescribed variable surface temperature and stretched with rapidly decreasing power law velocities. The effects of suction in the presence of a quiescent fluid medium of constant temperature are considered. Rosseland approximation is used to describe the radiative heat flux in the energy equation. The transformed governing equations are solved numerically and the velocity and temperature profiles as well as the local Nusselt number and skin friction coefficient are presented. Results show that the effect of radiation is to keep the molten mass away from the slot warmer, reduces the friction factor and increases the heat transfer rate compared to the case with no radiation.
Radiation effects on natural convection laminar flow from a horizontal circular cylinder
The effect of radiation on natural convection flow from an isothermal circular cylinder has been investigated numerically in this study. The governing boundary layer equations of motion are transformed into a non-dimensional form and the resulting nonlinear systems of partial differential equations are reduced to convenient boundary layer equations, which are then solved numerically by two distinct efficient methods namely: (i) implicit finite differencemethod or the Keller-Box Method (KBM) and (ii) Straight Forward Finite Difference Method (SFFD). Numerical results are presented by velocity and temperature distribution of the fluid as well as heat transfer characteristics, namely the shearing stress and the local heat transfer rate in terms of the local skin-friction coefficient and the local Nusselt number for a wide range of surface heating parameter and radiation-conduction parameter. Due to the effects of the radiation the skin-friction coefficients as well as the rate of heat transfer increased and consequently the momentum and thermal boundary layer thickness enhanced.