Laminar and turbulent natural convection flows induced by horizontal cylinders were investigated numerically. A finite difference scheme based on the integration of the governing equations over finite cells was applied to the two-dimensional steady-state (time averaged) problems. Laminar and turbulent flow predictions were obtained for natural convection around a horizontal cylinder with uniform and nonuniform wall boundary conditions and in concentric annulus where recirculation is prominent.;Natural convection around horizontal cylinders within confining walls and in interacting flow fields was treated by a system of overlapping Cartesian and cylindrical polar grid systems, the latter being used in the neighborhood of the cylinders and former in the remaining part of the flow. Single and double rows of closely spaced cylinders were considered where separate flow fields induced by individual surfaces interact with one another.;The solutions of the various problems considered were compared with experimental results and other numerical and analytical solutions to the extent that they were available in the literature.;A two-equation (k-(epsilon)) turbulence model was extended to include the effects of buoyancy and applied for predicting time averaged flow patterns, temperatures, turbulence intensity and turbulent viscosity in recirculating natural convection flows.
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