Suction-induced magnetohydrodynamics of a viscoelastic fluid over a stretching surface within a porous medium

摘要

The magnetohydrodynamic (MHD) flow over a stretching sheet of a viscoelastic fluid immersed in a porous medium is studied analytically. The flow is induced by suction and also by an infinite elastic sheet which is stretched along its own plane. The stretching of the sheet is assumed to be proportional to the distance from the slit. The governing equations are reduced to a non-linear ordinary differential equation by means of similarity transformation. The resulting non-linear equation is solved analytically and the streamlines of the flow field are obtained. The effect of various quantities such as suction parameter, Chandrasekhar number and porous parameter on the velocity fields are studied. Results show that the flow field can be divided into a near-field region (boundary-layer region) and a far-field region (free stream region). Suction on the surface plays an important role in the flow development in the near-field whereas the far-field is influenced mainly by stretching. The electromagnetic effect plays exactly the same role as the porous medium, which reduces the horizontal flow velocity resulting from stretching. The flow pattern also exhibits a substantial change as the suction effect increases, and in such case the growth of the nearfield region can extend far away from the stretching surface. These results have possible technological applications in liquid-based systems involving stretchable materials.