scholarly journals Thermal and solutal stratification in mixed convection three-dimensional flow of an Oldroyd-B nanofluid

2017 ◽  
Vol 7 ◽  
pp. 3797-3805 ◽  
Author(s):  
Tasawar Hayat ◽  
Ikram Ullah ◽  
Taseer Muhammad ◽  
Ahmed Alsaedi
Author(s):  
B Mahanthesh ◽  
B J Gireesha ◽  
R S R Gorla

Purpose – The purpose of this paper is to numerically solve the problem of an unsteady squeezing three-dimensional flow and heat transfer of a nanofluid in rotating vertical channel of stretching left plane. The fluid is assumed to be Newtonian, incompressible and electrically conducting embedded with nanoparticles. Effect of internal heat generation/ absorption is also considered in energy equation. Four different types of nanoparticles are considered, namely, copper (Cu), alumina (Al2O3), silver (Ag) and titanium oxide (TiO2) with the base fluid as water. Maxwell-Garnetts and Brinkman models are, respectively, employed to calculate the effective thermal conductivity and viscosity of the nanofluid. Design/methodology/approach – Using suitable similarity transformations, the governing partial differential equations are transformed into set of ordinary differential equations. Resultant equations have been solved numerically using Runge-Kutta-Fehlberg fourth fifth order method for different values of the governing parameters. Effects of pertinent parameters on normal, axial and tangential components of velocity and temperature distributions are presented through graphs and discussed in detail. Further, effects of nanoparticle volume fraction, squeezing parameter, suction/injection parameter and heat source/sink parameter on skin friction and local Nusselt number profiles for different nanoparticles are presented in tables and analyzed. Findings – Squeezing effect enhances the temperature field and consequently reduces the heat transfer rate. Large values of mixed convection parameter showed a significant effect on velocity components. Also, in many heat transfer applications, nanofluids are potentially useful because of their novel properties. They exhibit high-thermal conductivity compared to the base fluids. Further, squeezing and rotation effects are desirable in control the heat transfer. Originality/value – Three-dimensional mixed convection flows over in rotating vertical channel filled with nanofluid are very rare in the literature. Mixed convection squeezing three-dimensional flow in a rotating channel filled with nanofluid is first time investigated.


2013 ◽  
Vol 135 (4) ◽  
Author(s):  
M. Nawaz ◽  
T. Hayat ◽  
A. Alsaedi

This work is accomplished to investigate the Hall and ion-slip effects on mixed convection three-dimensional flow of a Maxwell fluid over a stretching vertical surface. The problem is first formulated and then nondimensionalized by using suitable variables. The solutions are computed by homotopy analysis method (HAM). The results are compared with the already limiting results. The convergence of derived series solutions is studied. The velocity components and temperature have been examined for several important parameters. Numerical computations for Nusselt number are presented and analyzed.


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