UNSTEADY MIXED CONVECTION FLOW FROM A SLENDER CYLINDER DUE TO IMPULSIVE CHANGE IN WALL VELOCITY AND TEMPERATURE

An unsteady mixed convection flow of a viscous incompressible fluid over a non-permeable linear stretching vertical slender cylinder is considered to investigate the combined effects of buoyancy force and thermal diffusion. It is assumed that the slender cylinder is in line with the flow. The unsteadiness in the flow and temperature fields is caused due to the impulsive change in the wall velocity and wall temperature of linearly stretching vertical slender cylinder. The effect of surface curvature is also taken into account, particularly for the applications as wire and fiber drawing where exact predictions are expected. The governing boundary layer equations are transformed into a non-dimensional form by a group of non-similar transformations. The resulting system of coupled non-linear partial differential equations is solved by an implicit finite difference scheme in combination with the quasi-linearization technique. Numerical computations are performed to understand the physical situations of linear stretching surface for different values of parameters to display the velocity and temperature profiles graphically. The numerical results for the local skin-friction coefficient and local Nusselt number are also presented. Present results are compared with previously published work and are found to be in excellent agreement.