scholarly journals Unsteady Natural Convection Flow past an Infinite Cylinder with Thermal and Mass Stratification

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Ashish Paul ◽  
Rudra Kanta Deka
Keyword(s):  
Schmidt Number ◽  
Infinite Cylinder ◽  
Convection Flow ◽  
Physical Parameters ◽  
Free Convection Flow ◽  
Fluid Medium ◽  
Flow Past ◽  
Laplace Transform Technique ◽  
Mass Stratification ◽  
Unsteady Natural Convection

This paper presents an analytical solution of unsteady one-dimensional free convection flow past an infinite vertical circular cylinder in a stratified fluid medium. The dimensionless coupled linear governing partial differential equations are solved by Laplace transform technique for unit Prandtl number and Schmidt number. Effects of various physical parameters are presented with graphs. Numerical values of boundary layer thickness for different parameters are presented in table. Due to the effects of thermal and mass stratifications, the velocity, temperature, and skin friction, Nusselt number shows oscillatory behaviour at smaller times and then reaches steady state at larger times.

The Effects of Radiation on Free Convection Flow with Ramped Wall Temperature in Brinkman Type Fluid

2013 ◽  
Vol 62 (3) ◽  
Author(s):  
Muhamad Najib Zakaria ◽  
Abid Hussanan ◽  
Ilyas Khan ◽  
Sharidan Shafie
Keyword(s):  
Nusselt Number ◽  
Free Convection ◽  
Laplace Transform ◽  
Vertical Plate ◽  
Convection Flow ◽  
Physical Parameters ◽  
Governing Equations ◽  
Free Convection Flow ◽  
Laplace Transform Technique ◽  
Effects Of Radiation

The present paper is on study of the influence of radiation on unsteady free convection flow of Brinkman type fluid near a vertical plate containing a ramped temperature profile. Using the appropriate variables, the basic governing equations are reduced to nondimensional equations valid with the imposed initial and boundary conditions. The exact solutions are obtained by using Laplace transform technique. The influence of radiation near a ramped temperature plate is also compared with the flow near a plate with constant temperature. The numerical computations are carried out for various values of the physical parameters such as velocity, temperature, skin friction and Nusselt number and presented graphically.

Unsteady free convection flow past a periodically accelerated vertical plate with Newtonian heating

2016 ◽  
Vol 26 (7) ◽  
pp. 2119-2138 ◽  
Author(s):  
M.C. Raju ◽  
S.V.K. Varma ◽  
A.J. Chamkha
Keyword(s):  
Mass Transfer ◽  
Free Convection ◽  
Skin Friction ◽  
Heat And Mass Transfer ◽  
Convection Flow ◽  
Convection Boundary Layer ◽  
Physical Parameters ◽  
Content Type ◽  
Flow Past ◽  
Laplace Transform Technique

Purpose The purpose of this paper is to present an analytical study for a problem of unsteady free convection boundary layer flow past a periodically accelerated vertical plate with Newtonian heating (NH). Design/methodology/approach The equations governing the flow are studied in the closed form by using the Laplace transform technique. The effects of various physical parameters are studied through graphs and the expressions for skin friction, Nusselt number and Sherwood number are also derived and discussed numerically. Findings It is observed that velocity, concentration and skin friction decrease with the increasing values of Sc whereas temperature distribution decreases in the increase in Pr in the presence of NH. Research limitations/implications This study is limited to a Newtonian fluid. This can be extended for non-Newtonian fluids. Practical implications Heat and mass transfer frequently occurs in chemically processed industries, distribution of temperature and moisture over agricultural fields, dispersion of fog and environment pollution and polymer production. Social implications Free convection flow of coupled heat and mass transfer occurs due to the temperature and concentration differences in the fluid as a result of driving forces. For example, in atmospheric flows, thermal convection resulting from heating of the earth by sunlight is affected differences in water vapor concentration. Originality/value The authors have studied heat and mass transfer effects on unsteady free convection boundary layer flow past a periodically accelerated vertical surface with NH, where the heat transfer rate from the bounding surface with a finite heat capacity is proportional to the local surface temperature, and which is usually termed as conjugate convective flow. The equations governing the flow are studied in the closed form by using the Laplace transform technique. The effects of various physical parameters are studied through graphs and the expression for skin friction also derived and discussed.

scholarly journals Heat and Mass Transfer of Unsteady Hydromagnetic Free Convection Flow Through Porous Medium Past a Vertical Plate with Uniform Surface Heat Flux

2017 ◽  
Vol 47 (3) ◽  
pp. 25-58 ◽  
Author(s):  
Mohamed Abd El-Aziz ◽  
Aishah S. Yahya
Keyword(s):  
Mass Transfer ◽  
Heat Flux ◽  
Porous Medium ◽  
Free Convection ◽  
Heat And Mass Transfer ◽  
Transport Model ◽  
Convection Flow ◽  
Physical Parameters ◽  
Free Convection Flow ◽  
Laplace Transform Technique

AbstractSimultaneous effects of thermal and concentration diffusions in unsteady magnetohydrodynamic free convection flow past a moving plate maintained at constant heat flux and embedded in a viscous fluid saturated porous medium is presented. The transport model employed includes the effects of thermal radiation, heat sink, Soret and chemical reaction. The fluid is considered as a gray absorbing-emitting but non-scattering medium and the Rosseland approximation in the energy equations is used to describe the radiative heat flux for optically thick fluid. The dimensionless coupled linear partial differential equations are solved by using Laplace transform technique. Numerical results for the velocity, temperature, concentration as well as the skin friction coefficient and the rates of heat and mass transfer are shown graphically for different values of physical parameters involved.

Transient Free Convection Flow Past an Infinite Moving Vertical Cylinder in a Stably Stratified Fluid

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
R. K. Deka ◽  
A. Paul
Keyword(s):  
Nusselt Number ◽  
Steady State ◽  
Skin Friction ◽  
Thermal Stratification ◽  
Fluid Velocity ◽  
Vertical Cylinder ◽  
Convection Flow ◽  
Physical Parameters ◽  
Flow Past ◽  
Laplace Transform Technique

This paper presents an analytical treatment for the unsteady one-dimensional natural convective flow past an infinite moving vertical cylinder in the presence of thermal stratification. Exact solutions of the dimensionless unsteady coupled linear governing equations are obtained, in terms of Bessel functions by the Laplace transform technique, for the tractable case of unit Prandtl number. Numerical computations for velocity, temperature, skin-friction, and Nusselt number are made for various set of physical parameters and presented in graphs. Due to the presence of thermal stratification, the fluid velocity and temperature approach steady state, whereas the corresponding flow in an unstratified fluid does not. The steady state is attained at smaller times as the stratification increases. Furthermore, in the presence of stratification, the skin-friction and Nusselt number approaches fixed value as time progresses, while for unstratified fluid, there is a gradual decrease as time increases.

scholarly journals Unsteady free convection flow of a micropolar fluid with Newtonian heating: Closed form solution

2017 ◽  
Vol 21 (6 Part A) ◽  
pp. 2313-2326 ◽  
Author(s):  
Abid Hussanan ◽  
Mohd Salleh ◽  
Ilyas Khan ◽  
Razman Tahar
Keyword(s):  
Free Convection ◽  
Closed Form ◽  
Micropolar Fluid ◽  
Closed Form Solution ◽  
Convection Flow ◽  
Physical Parameters ◽  
Newtonian Heating ◽  
Free Convection Flow ◽  
Present Solution ◽  
Laplace Transform Technique

This article investigates the unsteady free convection flow of a micropolar fluid over a vertical plate oscillating in its own plane with Newtonian heating condition. The problem is modelled in terms of partial differential equations with some physical conditions. Closed form solutions in terms of exponential and complementary error functions of Gauss are obtained by using the Laplace transform technique. They satisfy the governing equations and impose boundary and initial conditions. The present solution in the absence of microrotation reduces to well-known solutions of Newtonian fluid. Graphs are plotted to study the effects of various physical parameters on velocity and microrotation. Numerical results for skin friction and wall couple stress is computed in tables. Apart from the engineering point of view, the present article has strong advantage over the published literature as the exact solutions obtained here can be used as a benchmark for comparison with numerical/ approximate solutions and experimental data.

scholarly journals MASS TRANSFER OF FREE CONVECTION FLOW BETWEEN TWO PARALLEL OSCILLATING PLATES.

2019 ◽  
Vol 1 (2) ◽  
pp. 118-121
Author(s):  
Fasihah Zulkiflee ◽  
Sharidan Shafie ◽  
Ahmad Qushairi Mohamad
Keyword(s):  
Nusselt Number ◽  
Free Convection ◽  
Skin Friction ◽  
Schmidt Number ◽  
Convection Flow ◽  
Parallel Plates ◽  
Governing Equations ◽  
Free Convection Flow ◽  
Laplace Transform Technique ◽  
The Laplace Transform

This paper investigated unsteady free convection flow between two parallel plates with mass diffusion. One of the plate are considered oscillating. Appropriate non-dimensional variables are used to reduce the dimensional governing equations along with imposed initial and boundary conditions. The exact solution for velocity, temperature and concentration profiles are obtained using the Laplace Transform technique. The graphical results of the solutions are presented to illustrate the behavior of the fluid flow with the influenced of Schmidt number, Prandtl number, oscillating parameter, Grashof and mass Grashof number. The corresponding expressions for skin friction, Nusselt number and Sherwood number are also calculated. It is observed that increasing Prandtl and Schmidt number will increased the Nusselt number but decreased the skin friction.

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