Eur. Phys. J. Spec. Top. (2021) 230: 1331-1343
https://doi.org/10.1140/epjs/s11734-021-00055-7

Regular Article

Unsteady thin Casson-nanoliquid film flow over a porous stretching sheet

¹ Department of Mathematics, Sikkim Manipal Institute of Technology, Majitar, 737136, Rangpo, East Sikkim, India
² Department of Mathematics, Sikkim University, 6th Mile,, Tadong, Samdur, 737102, Gangtok, East Sikkim, India
³ Department of Mathematics, Manipur University, 795003, Canchipur, Imphal, Manipur, India
⁴ Department of Basic and Applied Science, National Institute of Technology, Yupia, 791112, Papumpare, Arunachal Pradesh, India

^a yogenghatani@gmail.com

Received: 22 September 2020
Accepted: 31 January 2021
Published online: 6 May 2021

Abstract

In this article, the flow of thin Casson-nanoliquid (CNL) film is examined over a porous stretching sheet with suction/injection and transverse magnetic. Appropriate similarity transformations are used to transmute the governing set of equations to a set of partial differential equations. Analytical expressions for the velocity and temperature fields are obtained by the singular perturbation technique. The non-linear film evolution equations for long time are solved by fourth-order Runge–Kutta method. It is observed that the thickness of the liquid film enhances with the nanoparticle volume fraction, Casson parameter, Hartmann number, and porosity parameter. The rate of film thinning increases for suction, whereas reverse phenomenon is found for injection. A curve $x=X_c$ is drawn within the CNL which divides total flow region in two parts, such that in one region, heat is transferred from sheet to the CNL film and on other zone from film to sheet.