scholarly journals Nonlinear Convection Flow of Micropolar Nanofluid due to a Rotating Disk with Multiple Slip Flow

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Chaluma Zemedu ◽  
Wubshet Ibrahim

In this analysis, steady, laminar, and two-dimensional boundary layer flow of nonlinear convection micropolar nanofluid due to a rotating disk is considered. The mathematical formulation for the flow problem has been made. By means of appropriate similarity transformation and dimensionless variables, the governing nonlinear boundary value problems were reduced into coupled high-order nonlinear ordinary differential equations with numerically solved. The equations were calculated using method bvp4c from matlab software for various quantities of main parameters. The influences of different parameters on skin friction coefficients f″0 and G′0, wall duo stress coefficients H1′0, -H2′0, and -H3′0, the Nusselt number -θ′0, and Sherwood number Ω′0, as well as the velocities, temperature, and concentration are analysed and discussed through tables and plotted graphs. The findings indicate that an increase in the values of thermal and solutal nonlinear convection parameters allow to increase the value of velocities f′η and Gη near surface of the disk and reduce at far away from the disk as well as thermal and solutal Grashof numbers tolerate to increase in the value of radial velocity f′η near surface of the disk.

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Wubshet Ibrahim ◽  
Chaluma Zemedu

In this paper, two-dimensional steady laminar boundary layer flow of a nonlinear mixed convection flow of micropolar nanofluid with Soret and magnetic field effect over a nonisothermal sphere is evaluated. The mathematical formulation for the flow problem has been made with appropriate similarity transformation and dimensionless variables, and the main nonlinear boundary value problems were reduced into mixed high-order nonlinear ordinary differential equations. Solution for velocity, microrotation, temperature, and concentration has been obtained numerically. The equations were calculated using method bvp4c from Matlab software for various quantities of main parameters. The effects of various parameters on skin friction coefficient f″0, wall duo stress coefficient -G′0, and convection mass transfer coefficient -Φ′0 are analysed and presented through the graphs and tables. The convergence test has been maintained. For the number of points greater than the suitable mesh number of points, the precision is not influenced but the set time is increased. Moreover, a comparison with a previous paper, obtainable in the literature, has been presented and an excellent agreement is obtained. The findings indicate that an increase in the values of nonisothermal parameters (m, P), magnetic Ma, thermal and solutal nonlinear convection (λ, s) parameter, and Soret number is to enhance the temperature difference between the boundary layer and ambient fluid to diffuse which increases the velocity profile f′ζ and their boundary layer thicknesses near the surface of the sphere.


2015 ◽  
Vol 70 (4) ◽  
pp. 225-233 ◽  
Author(s):  
Tasawar Hayat ◽  
Taseer Muhammad ◽  
Sabir Ali Shehzad ◽  
Ahmed Alsaedi

AbstractIn this article we investigated the characteristics of Brownian motion and thermophoresis in the magnetohydrodynamic (MHD) three-dimensional boundary layer flow of an incompressible Jeffrey fluid. The flow is generated by a bidirectional stretching surface. Fluid is electrically conducting in the presence of a constant applied magnetic field. Mathematical formulation of the considered flow problem is made through the boundary layer analysis. A newly proposed boundary condition requiring zero nanoparticle mass flux is employed in the flow analysis of Jeffrey fluid. The governing nonlinear boundary layer equations are reduced into the nonlinear ordinary differential systems through appropriate transformations. The resulting systems have been solved for the velocities, temperature, and nanoparticle concentration expressions. The contributions of various interesting parameters are studied graphically. The values of the Nusselt number are computed and examined.


2019 ◽  
Vol XVI (2) ◽  
pp. 13-22
Author(s):  
Muhammad Ehtisham Siddiqui

Three-dimensional boundary-layer flow is well known for its abrupt and sharp transition from laminar to turbulent regime. The presented study is a first attempt to achieve the target of delaying the natural transition to turbulence. The behaviour of two different shaped and sized stationary disturbances (in the laboratory frame) on the rotating-disk boundary layer flow is investigated. These disturbances are placed at dimensionless radial location (Rf = 340) which lies within the convectively unstable zone over a rotating-disk. Mean velocity profiles were measured using constant-temperature hot-wire anemometry. By careful analysis of experimental data, the instability of these disturbance wakes and its estimated orientation within the boundary-layer were investigated.


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