Magnetohydrodynamic effects on the free convective flow over a moving vertical cylinder

Abstract

This thesis discusses the theoretical and numerical solutions of the magnetohydrodynamic effects on the free convective flow, past an impulsively started moving semi-infinite vertical cylinder, in the presence of heat and mass transfer with/without thermal radiation or chemical reaction and various boundary conditions. Initially, the cylinder and the fluid are of the same temperature and concentration. The governing equations of free convection are simplified by invoking the boundary layer at the Boussinesq s approximations. The governing equations are transformed into a dimensionless form, by using suitable non-dimensional quantities. The effects of the velocity, temperature and concentration fields in the transient and steady-state are studied for various parameters, like the magnetic field, radiation, chemical reaction and time, presented in the form of graphs and tables. The numerical solution of the magnetohydrodynamic effects on the unsteady natural convection flow of a viscous incompressible fluid past an impulsively started semi-infinite vertical cylinder in the presence of heat and mass transfer has been discussed for the boundary conditions of (i) temperature oscillation and (ii) uniform heat and mass flux. The stability of the finite difference scheme of the Crank-Nicolson type is analyzed, using the Von-Neumann technique. The numerical results are presented in the form of graphs for various values of the parameters. In order to ascertain the accuracy of the numerical results, the present studies are compared with the available theoretical solutions in the literature, and they are found to be in good agreement. The present work is more concerned with the transient part. The time taken to reach the steady state is observed for various values of parameters. The fluid considered in this study is air. The effects of the velocity, temperature and the concentration fields in the transient and steady state are studied. The local and average values of the skin-friction, Nusselt number and Sherwood number are