Eur. Phys. J. Plus (2016) 131: 49
https://doi.org/10.1140/epjp/i2016-16049-y

Regular Article

Unsteady flow of thin nanoliquid film over a stretching sheet in the presence of thermal radiation

Department of Mathematics, National Institute of Technology, Arunachal Pradesh, Yupia, 791112, Papumpare, India

^* e-mail: susantamaiti@gmail.com

Received: 10 November 2015
Revised: 20 January 2016
Accepted: 21 January 2016
Published online: 29 February 2016

Abstract

Unsteady two-dimensional flow of a thin nanoliquid film over an impulsively stretching sheet is studied in the presence of thermal radiation. It is assumed that the sheet is either heating or cooling along the stretching direction. The nonlinear governing set of equations is solved analytically by the singular-perturbation technique. It is observed that the film thinning rate decreases with the increase of the nanoparticle volume fraction. It is also found that the rate of film thinning decreases with the increase of the radiation parameter in case of heating and the opposite phenomenon is observed for cooling of the sheet. The film thinning rate increases with the increase of the nanolayer thickness but decreases with the increase of the nanoparticle radius when the sheet is heated. Moreover, it is observed that the temperature gradient T_z changes its sign within the film in the presence of thermal radiation.