Asia Anjum

Analytic approximate solutions for time-dependent flow and heat transfer of a Sisko fluid

Purpose – The purpose of this paper is to find analytic approximate solutions for time-dependent flow and heat transfer of a Sisko fluid. Design/methodology/approach – The homotopy analysis method is used to find a family of travelling wave solutions of the governing non-linear problem. Findings – The effects of different parameters on the velocity and temperature profiles are shown graphically. Originality/value – The analytic solutions of the system of non-linear ordinary differential equations are constructed in the series form for various values of the power index.

Some Unsteady Flows of a Jeffrey Fluid between Two Side Walls over a Plane Wall

In this paper, some time-dependent flows of a non-Newtonian fluid between two side walls over a plane wall are investigated. The following three problems have been studied: (i) flow due to an oscillating plate, (ii) flow due to an accelerating plate, and (iii) flow due to applied constant stress. The explicit expressions for the velocity field are determined by using the integral transforms. The solutions that have been obtained, depending on the initial and boundary conditions, are written as sum of the steady state and transient solutions. The similar solutions for second-grade and Newtonian fluids can be deduced as limiting cases of our solutions. Furthermore, in absence of the side walls they reduce to the similar solutions over an infinite plate. The effects of some important parameters due to side walls on the flow field are investigated.

ANALYTIC SOLUTIONS FOR MHD FLOWS OF AN OLDROYD-B FLUID BETWEEN TWO SIDEWALLS PERPENDICULAR TO THE PLATE

This study is concerned with analytic solutions of some magnetohydrodynamic (MHD) flows of an Oldroyd-B fluid. The fluid is assumed to be electrically conducting in the presence of a uniform magnetic field and occupies the space over a flat plate between two sidewalls perpendicular to the plate. The governing equation of motion is treated analytically, yielding the derivation of exact solutions under integral and series form. By assigning numerical values to various parameters, the integrals encountered are evaluated numerically. In the absence of sidewalls, all solutions that have been obtained reduce to those corresponding to the motion over an infinite plate. The impacts of several quantities are investigated on the resulting velocity field and the tangential stress at the bottom wall.