scholarly journals Three-Dimensional Magnetohydrodynamic Mixed Convection Flow of Nanofluids over a Nonlinearly Permeable Stretching/Shrinking Sheet with Velocity and Thermal Slip

2018 ◽  
Vol 8 (7) ◽  
pp. 1128 ◽  
Author(s):  
Anuar Jamaludin ◽  
Roslinda Nazar ◽  
Ioan Pop
Keyword(s):  
Differential Equations ◽  
Mixed Convection ◽  
Ordinary Differential Equations ◽  
Three Dimensional ◽  
Convection Flow ◽  
Shrinking Sheet ◽  
Lower Branch ◽  
Mixed Convection Flow ◽  
Branch Solution ◽  
Convection Parameter

In this paper, the steady three-dimensional magnetohydrodynamic (MHD) mixed convection flow of nanofluids over a permeable vertical stretching/shrinking sheet with slip conditions is investigated in a numerical manner. As such, two types of nanofluids, Cu-water and Ag-water, had been considered. A similarity transformation was employed to reduce the governing equations to ordinary differential equations, which were then solved numerically using the MATLAB (Matlab R2015a, MathWorks, Natick, MA, USA, 1984) programme bvp4c. The numerical solutions derived from the ordinary differential equations subjected to the associated boundary conditions, were obtained to represent the values of the mixed convection parameter. Dual (upper and lower branch) solutions were discovered in the opposing flow region of the mixed convection parameter. A stability analysis was carried out to prove that the upper branch solution was indeed stable, while the lower branch solution was unstable. The significant effects of the governing parameters on the reduced skin friction coefficients, the reduced local Nusselt number, as well as the velocity and temperature profiles, were presented graphically and discussed in detail.

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.

scholarly journals HYDROMAGNETIC MIXED CONVECTION FLOW OF AN EXOTHERMIC FLUID IN A VERTICAL CHANNEL

2019 ◽  
Vol 1 (1) ◽  
pp. 19-37
Author(s):  
Abdulazeez Sheriff ◽  
Murtala Sani
Keyword(s):  
Nusselt Number ◽  
Differential Equations ◽  
Mixed Convection ◽  
Ordinary Differential Equations ◽  
Skin Friction ◽  
Sherwood Number ◽  
Vertical Channel ◽  
Transformation Method ◽  
Convection Flow ◽  
Mixed Convection Flow

In this paper, Hydromagnetic mixed convection flow of an exothermic fluid in a vertical channel is considered. The dimensionless ordinary differential equations were solved using differential transformation method (DTM) to obtain the expression of velocity, temperature and concentration. From momentum, energy and mass equations.  The effect of Skin friction, Nusselt number and Sherwood number with various parameters on velocity, temperature and concentration are presented and discussed. The result indicated that the effect of t, is to increase the Skin friction while K increases it at upper plate and suppresses it at lower plate.

Mixed Convection Flow of a Micropolar Fluid Past a Vertical Stretching Surface in a Thermally Stratified Porous Medium with Thermal Radiation

2013 ◽  
Vol 29 (3) ◽  
pp. 461-470 ◽  
Author(s):  
Mostafa A.A. Mahmoud ◽  
Shimaa E. Waheed
Keyword(s):  
Porous Medium ◽  
Differential Equations ◽  
Mixed Convection ◽  
Thermal Radiation ◽  
Ordinary Differential Equations ◽  
Micropolar Fluid ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Linear Ordinary Differential Equations ◽  
Permeability Parameter

AbstractThis paper is concerned with the effect of thermally stratification on the steady, two-dimensional mixed convection flow of a micropolar fluid past a vertical stretching permeable surface saturated in porous medium taking into account the effect of thermal radiation. The governing system of partial differential equations describing the problem are converted into a system of non-linear ordinary differential equations using similarity transformation. The resulting system of coupled nonlinear ordinary differential equations is solved numerically using the Chebyshev spectral method. The numerical results for the velocity, the micro-rotation and the temperature are displayed graphically showing the effects of various parameters like the buoyancy parameter, the radiation parameter, the stratification parameter, the permeability parameter and the suction/injection parameter. Moreover, the numerical values of the local skinfriction coefficient, the wall couple stress and the local Nusselt number for these parameters are also tabulated and discussed.

Three-dimensional mixed convection flow of viscoelastic nanofluid over an exponentially stretching surface

2015 ◽  
Vol 25 (2) ◽  
pp. 333-357 ◽  
Author(s):  
Tasawar Hayat ◽  
Bilal Ashraf ◽  
Sabir Ali Shehzad ◽  
A. Alsaedi ◽  
N. Bayomi
Keyword(s):  
Differential Equations ◽  
Mixed Convection ◽  
Three Dimensional ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Stretching Surface ◽  
Content Type ◽  
Viscoelastic Nanofluid ◽  
Exponentially Stretching Surface ◽  
Exponentially Stretching

Purpose – The purpose of this paper is to investigate the three-dimensional mixed convection flow of viscoelastic nanofluid induced by an exponentially stretching surface. Design/methodology/approach – Similarity transformations are utilized to reduce the partial differential equations into the ordinary differential equations. The corresponding non-linear problems are solved by homotopy analysis method. Findings – The authors found that an increase in thermophoresis and Brownian motion parameter enhance the temperature. Here thermal conductivity of fluid is enhanced due to which higher temperature and thicker thermal boundary layer thickness is obtained. Practical implications – Heat and mass transfer effects in mixed convection flow over a stretching surface have numerous applications in the polymer technology and metallurgy. Such flows are encountered in metallurgical processes which involve the cooling of continuous strips or filaments by drawing them through a quiescent fluid and that in the process of drawing, these strips are sometimes stretched. Originality/value – Three-dimensional flows over an exponentially stretching surface are very rare in the literature. Three-dimensional flow of viscoelastic nanofluid due to an exponentially stretching surface is first time investigated.

scholarly journals Computational Study of the Coupled Mechanism of Thermophoretic Transportation and Mixed Convection Flow around the Surface of a Sphere

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2694
Author(s):  
Amir Abbas ◽  
Muhammad Ashraf ◽  
Yu-Ming Chu ◽  
Saqib Zia ◽  
Ilyas Khan ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Partial Differential Equations ◽  
Differential Equations ◽  
Mixed Convection ◽  
Computational Study ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Partial Differential ◽  
Primitive Form ◽  
The Mathematical Model

The main goal of the current work was to study the coupled mechanism of thermophoretic transportation and mixed convection flow around the surface of the sphere. To analyze the characteristics of heat and fluid flow in the presence of thermophoretic transportation, a mathematical model in terms of non-linear coupled partial differential equations obeying the laws of conservation was formulated. Moreover, the mathematical model of the proposed phenomena was approximated by implementing the finite difference scheme and boundary value problem of fourth order code BVP4C built-in scheme. The novelty point of this paper is that the primitive variable formulation is introduced to transform the system of partial differential equations into a primitive form to make the line of the algorithm smooth. Secondly, the term thermophoretic transportation in the mass equation is introduced in the mass equation and thus the effect of thermophoretic transportation can be calculated at different positions of the sphere. Basically, in this study, some favorite positions around the sphere were located, where the velocity field, temperature distribution, mass concentration, skin friction, and rate of heat transfer can be calculated simultaneously without any separation in flow around the surface of the sphere.

scholarly journals Benchmark Solution for a Three-Dimensional Mixed-Convection Flow, Part 1: Reference Solutions

2011 ◽  
Vol 60 (5) ◽  
pp. 325-345 ◽  
Author(s):  
Xavier Nicolas ◽  
Marc Medale ◽  
Stéphane Glockner ◽  
Stéphane Gounand
Keyword(s):  
Mixed Convection ◽  
Three Dimensional ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Flow Part ◽  
Benchmark Solution

Cross flow and heat transfer past a permeable stretching/shrinking sheet in a hybrid nanofluid

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Natalia C. Roşca ◽  
Alin V. Roşca ◽  
Amin Jafarimoghaddam ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Cross Flow ◽  
Porous Wall ◽  
Shrinking Sheet ◽  
Hybrid Nanofluid ◽  
Lower Branch ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Branch Solution

Purpose The purpose of this paper is to study the laminar boundary layer cross flow and heat transfer on a rotational stagnation-point flow over either a stretching or shrinking porous wall submerged in hybrid nanofluids. The involved boundary layers are of stream-wise type with stretching/shrinking process along the surface. Design/methodology/approach Using appropriate similarity variables the partial differential equations are reduced to ordinary (similarity) differential equations. The reduced system of equations is solved analytically (by high-order perturbed field propagation for small to moderate stretching/shrinking parameter and low-order perturbation for large stretching/shrinking parameter) and numerically using the function bvp4c from MATLAB for different values of the governing parameters. Findings It was found that the basic similarity equations admit dual (upper and lower branch) solutions for both stretching/shrinking surfaces. Moreover, performing a linear stability analysis, it was confirmed that the upper branch solution is realistic (physically realizable), while the lower branch solution is not physically realizable in practice. These dual solutions will be studied in the present paper. Originality/value The authors believe that all numerical results are new and original and have not been published before for the present problem.

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