Study of special types of boundary layer natural convection flow problems through the clique polynomial method

Heat Transfer ◽  
2021 ◽  
Author(s):  
S. Kumbinarasaiah ◽  
K. R. Raghunatha
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Polynomial Method ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Flow Problems

NUMERICAL AND ANALYTICAL SOLUTIONS FOR NATURAL CONVECTION FLOW WITH THERMAL RADIATION AND MASS TRANSFER PAST A MOVING VERTICAL POROUS PLATE BY DQM AND HAM

2011 ◽  
Vol 08 (03) ◽  
pp. 611-631 ◽  
Author(s):  
P. TALEBIZADEH ◽  
M. A. MOGHIMI ◽  
A. KIMIAEIFAR ◽  
M. AMERI
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Natural Convection ◽  
Thermal Radiation ◽  
Differential Quadrature Method ◽  
Porous Plate ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Homotopy Analysis ◽  
Excellent Method

In this paper, the boundary-layer natural convection flow on a permeable vertical plate with thermal radiation and mass transfer is studied when the plate moves in its own plane. A uniform temperature with uniform species concentration at the plate is affected and the fluid is considered to be a gray, absorbing–emitting. A viscous flow model is presented using boundary-layer theory comprising the momentum, energy, and concentration equations, which is solved analytically by means of an excellent method called homotopy analysis method (HAM). First, a comparison between HAM results and those obtained by means of a higher-order numerical method, namely differential quadrature method (DQM), is done. Close agreement of two sets of results indicates the accuracy of the HAM. The velocity, temperature, and concentration distributions are displayed graphically, and a parametric study is performed in which the effect of various parameters on the skin friction, the local Nusselt number (Nn), and the local Sherwood number (Mu) are investigated.

Transient two-dimensional natural convection flow of a nanofluid past an isothermal vertical plate using Buongiorno’s model

2017 ◽  
Vol 27 (1) ◽  
pp. 23-47 ◽  
Author(s):  
Marneni Narahari ◽  
Suresh Kumar Raju Soorapuraju ◽  
Rajashekhar Pendyala ◽  
Ioan Pop
Keyword(s):  
Boundary Layer ◽  
Nusselt Number ◽  
Brownian Motion ◽  
Natural Convection ◽  
Vertical Plate ◽  
Volume Fraction ◽  
Convection Flow ◽  
Nanoparticle Volume Fraction ◽  
Natural Convection Flow ◽  
Content Type

Purpose The purpose of this paper is to present a numerical investigation of the transient two-dimensional natural convective boundary-layer flow of a nanofluid past an isothermal vertical plate by incorporating the effects of Brownian motion and thermophoresis in the mathematical model. Design/methodology/approach The problem is formulated using the Oberbeck–Boussinesq and the standard boundary-layer approximations. The governing coupled non-linear partial differential equations for conservation of mass, momentum, thermal energy and nanoparticle volume fraction have been solved by using an efficient implicit finite-difference scheme of the Crank–Nicolson type, which is stable and convergent. Numerical computations are performed and the results for velocity, temperature and nanoparticle volume fraction are presented in graphs at different values of system parameters such as Brownian motion parameter, thermophoresis parameter, buoyancy ratio parameter, Prandtl number, Lewis number and dimensionless time. The results for local and average skin-friction and Nusselt number are also presented graphically and discussed thoroughly. Findings It is found that the velocity, temperature and nanoparticle volume fraction profiles enhance with respect to time and attain steady-state values as time progresses. The local Nusselt number is found to decrease with increasing thermophoresis parameter, while it increases slightly with increasing Brownian motion parameter. To validate the present numerical results, the steady-state local Nusselt number results for the limiting case of a regular fluid have been compared with the existing well-known results at different Prandtl numbers, and the results are found to be in an excellent agreement. Research limitations/implications The present analysis is limited to the transient laminar natural convection flow of a nanofluid past an isothermal semi-infinite vertical plate in the absence of viscous dissipation and thermal radiation. The unsteady natural convection flow of a nanofluid will be investigated for various physical conditions in a future work. Practical implications Unsteady flow devices offer potential performance improvements as compared with their steady-state counterparts, and the flow fields in the unsteady flow devices are typically transient in nature. The present study provides very useful information for heat transfer engineers to understand the heat transfer enhancement with the nanofluid flows. The present results have immediate relevance in cooling technologies. Originality/value The present research work is relatively original and illustrates the transient nature of the natural convective nanofluid boundary-layer flow in the presence of Brownian motion and thermophoresis.

Mixing in internally heated natural convection flow and scaling for a quasi-steady boundary layer

2014 ◽  
Vol 763 ◽  
pp. 352-368 ◽  
Author(s):  
Tae Hattori ◽  
John C. Patterson ◽  
Chengwang Lei
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Theoretical Analysis ◽  
Layer Thickness ◽  
Mixed Layer ◽  
Water Body ◽  
Temperature Stratification ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Penetration Length

AbstractThis study considers the natural convection flow in a water body subjected to heating by solar radiation. The investigation into this type of natural convection flow has been motivated by the fact that it is known to play a crucial role in the daytime heat and mass transfer in shallow regions of natural water reservoirs and lakes, with a resultant impact on biological activity. An analytical solution for temperature in such an internally heated system shows that the temperature stratification consists of an upper stable stratification and a lower unstable stratification. One of the important consequences of such a nonlinear temperature stratification is the limitation of the mixing driven by rising thermal plumes with the penetration length scale of the plumes determining the lower mixed layer thickness. A theoretical analysis conducted in the present study suggests that in relatively deep waters, the lower mixed layer thickness is equal to the attenuation length of the radiation, which has important implications for water quality, including the transport of pollutants and nutrients in the water body. Scalings are also obtained for the quasi-steady boundary layer. The theoretical analysis is validated against numerical simulations.

scholarly journals Conjugate Effects of Heat and Mass Transfer on Natural Convection Flow Across an Isothermal Horizontal Circular Cylinder With Chemical Reaction

2007 ◽  
Vol 12 (2) ◽  
pp. 191-201 ◽  
Author(s):  
Md. A. Hye ◽  
Md. M. Molla ◽  
M. A. H. Khan
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Chemical Reaction ◽  
Transfer Rate ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Species Concentration ◽  
Local Skin ◽  
Boundary Layer Equations ◽  
Wide Range

Natural convection flow across an isothermal cylinder immersed in a viscous incompressible fluid in the presence of species concentration and chemical reaction has been investigated. The governing boundary layer equations are transformed into a system of non-dimensional equations and the resulting nonlinear system of partial differential equations is reduced to a system of local non-similarity boundary layer equations, which is solved numerically by a very efficient implicit finite difference method together with the Keller-box scheme. Numerical results are presented by the velocity, temperature and species concentration profiles of the fluid as well as the local skin-friction coefficient, local heat transfer rate and local species concentration transfer rate for a wide range of chemical reaction parameter γ (γ = 0.0, 0.5, 1.0, 2.0, 4.0), buoyancy ratio parameter N (N = −1.0, −0.5, 0.0, 0.5, 1.0), Schmidt number Sc (Sc = 0.7, 10.0, 50.0, 100.0) andPrandtl number Pr (Pr = 0.7, 7.0).

Viscous dissipation in external natural convection flows

1969 ◽  
Vol 38 (1) ◽  
pp. 97-107 ◽  
Author(s):  
B. Gebhart ◽  
J. Mollendorf
Keyword(s):  
Boundary Layer ◽  
Natural Convection ◽  
Viscous Dissipation ◽  
Power Law ◽  
Surface Condition ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Wide Range ◽  
Prandtl Numbers ◽  
General Aspects

The effects of viscous dissipation are considered for external natural convection flow over a surface. A class of similar boundary-layer solutions is given and numerical results are presented for a wide range of the dissipation and Prandtl numbers. Several general aspects of similarity conditions for flow over surfaces and in convection plumes are discussed and their special characteristics considered. The general equations including the dissipation effect are given for the non-similar power law surface condition.

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