Transient features of mass diffusion of MHD slip flow over an unsteady permeable stretching sheet in the presence of a moving free stream, destructive/constructive chemical reaction and variable mass flux

Abstract

An investigation is carried out to explore the combined effects of Thompson–Troian (T–T) slip and variable mass flux on the mass diffusion of unsteady flow of viscous liquid passing a permeable stretched surface. Constructive/destructive chemical reaction has also been considered in this study. In several engineering sectors including aerodynamics, for HVAC (heating, ventilation and air conditioning) systems, it is essential to have a clear idea about the free stream velocity and how to control it. Trusting on this fact, moving free stream is considered here. This, along with the T–T slip, makes the present research distinct. With the help of ‘similarity transformations’, the governing equations along with the conditions at the boundary are transformed to self-similar forms and using fourth-order Runge–Kutta method with shooting technique by the help of bvp4c package in MATLAB software, solutions are obtained numerically. The influences of relevant parameters on the flow, solute distribution, shear stress and concentration at the surface are analysed in detail. Due to enhanced values of unsteadiness, slip and magnetic parameter, flow velocity decreases. Fluid concentration rises for rising strength of the magnetic field and slip whereas increasing unsteadiness causes the fluid concentration to decrease. Flow velocity is boosted up for rising values of velocity ratio parameter. When the slip parameter increases from 0.1 to 0.5, \(36.323\%\) increase in velocity gradient and \(8.262\%\) increase in surface concentration occur. When the slip parameter increases from 0.1 to 0.5, 36.323% increase in velocity gradient and 8.262% increase in surface concentration occur.