Eur. Phys. J. Plus (2017) 132: 146
https://doi.org/10.1140/epjp/i2017-11408-x

Regular Article

Double stratification in the MHD flow of a nanofluid due to a rotating disk with variable thickness

¹ Department of Mathematics, Quaid-I-Azam University 45320, 44000, Islamabad, Pakistan
² Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, 21589, Jeddah, Saudi Arabia

^* e-mail: mi_qau@yahoo.com

Received: 1 February 2017
Accepted: 13 February 2017
Published online: 27 March 2017

Abstract

In this article the MHD flow of a nanofluid is examined due to a variable-thickness rotating disk. Heat and mass transfer analysis is done by utilizing the effects of thermal and solutal stratification. Governing partial differential equations are simplified by applying boundary layer approximation. The resulting equations are further converted to ordinary differential equations by making suitable deformations. How various physical parameters are influencing velocities, temperature, concentration, heat transfer rate and surface drag force is examined briefly. Behavior of these relevant parameters is presented graphically to make a comprehensive discussion of results. Axial and radial velocities are increasing for larger exponent of the power law fluid. Temperature is a decreasing function of the Prandtl number while it causes an increase in the heat transfer rate. Increasing values of thermal stratification and solutal stratification parameters result in the reduction of temperature and concentration, respectively.