A numerical study of the vertical two-dimensional natural convection flow over a heated vertical surface and that in a thermal plume, the ambient medium being stably stratified due to a temperature increase with height, is carried out. Employing finite difference techniques, these buoyancy-induced flows are studied at various stratification levels, ambient temperature distributions and at two Prandtl numbers, 6.7 and 0.7, which apply for water and air at normal temperatures. The temperature and velocity fields are determined and the downstream variation of the centerline velocity and temperature for the plume are studied. The effect of thermal stratification on the flow and heat transfer mechanisms is determined. For the plume flow, it is found that buoyancy level decreases downstream, leading to a finite height to which the flow rises in a stratified environment. For the flow adjacent to a vertical plate too, the velocity and the buoyancy levels are found to be lowered due to stratification. The numerical scheme is outlined and its accuracy and convergence discussed. The results are found to be in good agreement with earlier studies of natural convection flows in thermally stratified media.
All Science Journal Classification (ASJC) codes
- Computer Science(all)