Flow and Heat Transfer Analysis of Fluids of Variable Viscosity

Abstract

In most of the studies conducted in fluid dynamics the fluid viscosity is usually assumed to be constant. However, experiments indicate that this assumption only make::; ::;en::;e if temperature doe::; not change rapidly and the fluid body i::; homogeneous for the application of interest. In this thesis we report the Steady IV nsteady boundary layer flow problems in which viscosity is either a function of temperature or of a space variable. Heat and mass transfer analysis have also been carried out where the flat surface is considered as a stretching sheet. In each case the skin friction and the rate of heat transfer has been reported. The issue of cooling has been discussed in detail. Vve have addressed this issue on different geometries considering various flow conditions such as unsteady flow over a stretching sheet which is embedded in porous medium; stagnation point flow over a permeable flat surface; flow through collapsible tube, and the oscillatory flow in a tube of varying cross section. Similarity transformations have been used in order to normalize the problem. The reduced governing nonlinear differential equations are solved analytically by using the homotopy analysis method and the perturbation method. The results are purely analytic and highly accurate. The accuracy of results has been proved by calculating the squared residual errors and (or) giving the comparison by calculating the numerical results.