scholarly journals Effect of thermal radiation on unsteady mixed convection flow near forward stagnation point over a cylinder of elliptic cross section

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 243-254 ◽  
Author(s):  
Tariq Javed ◽  
Irfan Mustafa ◽  
Hussain Ahmad
Keyword(s):  
Nusselt Number ◽  
Mixed Convection ◽  
Thermal Radiation ◽  
Stagnation Point ◽  
Cross Section ◽  
Convection Flow ◽  
Elliptic Cross Section ◽  
Mixed Convection Flow ◽  
Unsteady Mixed Convection ◽  
Elliptic Cross

The effect of thermal radiation on unsteady mixed convection flow near a forward stagnation point over a cylinder of elliptic cross section is investigated in this paper. The governing equations are transformed into dimensionless partial differential equations by using a suitable transformation and then are solved numerically by using an implicit finite difference scheme known as Keller Box method. The accuracy of the results is verified by comparing the obtained results with the previous studies available in the literature. It is shown that the results are highly accurate and are in good agreement. The separation times for both blunt and slender orientations in the presence of thermal radiation are shown in tabular forms. Moreover, the effects of pertinent parameters including Prandtl number Pr, mixed convection parameter ?, thermal radiation parameter Rd, surface temperature parameter qw and blunt/slender orientation parameter w on the velocity profile, the temperature profile and the Nusselt number are shown graphically. From the present study, it is observed that boundary layer separation occurs early due to thermal radiation and Nusselt number increases for both blunt and slender orientations.

scholarly journals Effects of Thermal Radiation on Mixed Convection Flow of a Micropolar Fluid from an Unsteady Stretching Surface with Viscous Dissipation and Heat Generation/Absorption

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Khilap Singh ◽  
Manoj Kumar
Keyword(s):  
Mixed Convection ◽  
Thermal Radiation ◽  
Heat Generation ◽  
Micropolar Fluid ◽  
Numerical Solutions ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Stretching Surface ◽  
Local Skin ◽  
Unsteady Mixed Convection

A numerical model is developed to examine the effects of thermal radiation on unsteady mixed convection flow of a viscous dissipating incompressible micropolar fluid adjacent to a heated vertical stretching surface in the presence of the buoyancy force and heat generation/absorption. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. The model contains nonlinear coupled partial differential equations which have been converted into ordinary differential equation by using the similarity transformations. The dimensionless governing equations for this investigation are solved by Runge-Kutta-Fehlberg fourth fifth-order method with shooting technique. Numerical solutions are then obtained and investigated in detail for different interesting parameters such as the local skin-friction coefficient, wall couple stress, and Nusselt number as well as other parametric values such as the velocity, angular velocity, and temperature.

Unsteady mixed convection flow at a three-dimensional stagnation point

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amin Noor ◽  
Roslinda Nazar ◽  
Kohilavani Naganthran ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Three Dimensional ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Unsteady Mixed Convection

Purpose This paper aims to probe the problem of an unsteady mixed convection stagnation point flow and heat transfer past a stationary surface in an incompressible viscous fluid numerically. Design/methodology/approach The governing nonlinear partial differential equations are transformed into a system of ordinary differential equations by a similarity transformation, which is then solved numerically by a Runge – Kutta – Fehlberg method with shooting technique and a collocation method, namely, the bvp4c function. Findings The effects of the governing parameters on the fluid flow and heat transfer characteristics are illustrated in tables and figures. It is found that dual (upper and lower branch) solutions exist for both the cases of assisting and opposing flow situations. A stability analysis has also been conducted to determine the physical meaning and stability of the dual solutions. Practical implications This theoretical study is significantly relevant to the applications of the heat exchangers placed in a low-velocity environment and electronic devices cooled by fans. Originality/value The case of suction on unsteady mixed convection flow at a three-dimensional stagnation point has not been studied before; hence, all generated numerical results are claimed to be novel.

Influence of Thermal Radiation on the Unsteady Mixed Convection Flow of a Jeffrey Fluid over a Stretching Sheet

2010 ◽  
Vol 65 (8-9) ◽  
pp. 711-719 ◽  
Author(s):  
Tasawar Hayat ◽  
Meraj Mustafa
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Thermal Radiation ◽  
Deborah Number ◽  
Convection Flow ◽  
Jeffrey Fluid ◽  
Mixed Convection Flow ◽  
Suction Parameter ◽  
Unsteady Mixed Convection ◽  
Homotopy Analysis

This study is concerned with the effect of thermal radiation on the unsteady mixed convection flow of a Jeffrey fluid past a porous vertical stretching surface. The arising problems of flow and heat transfer are solved analytically by employing homotopy analysis method (HAM). It is observed that the flow field is influenced appreciably by the unsteadiness parameter ζ , suction parameter S, mixed convection parameter λ , Deborah number β , Prandtl number Pr, and the radiation parameter Nr. Our performed computations depict that the heat transfer rate is increased with increasing values of Pr, Nr, and ζ

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