Numerical study of the laminar natural convection flow around horizontal isothermal cylinder

Natural convection around a horizontal circular cylinder under constant temperature or constant heat flux conditions in an infinite space has been the subject of numerous investigations in recent years. However, these studies use the inflow-outflow boundary in cylindrical coordinates that gives a sensible error, especially when the Rayleigh number is small. This investigation, that enters within the framework of general study dealing with natural convection from an array of cylinders, states the problem in cartesian coordinates system, involves the use of a control-volume method and resolves various apparent redundancies in boundary conditions. This problem was investigated numerically for laminar case by solving the full vorticity transport equation together with the stream function and energy equations. Results are obtained for 101 < Ra < 106 and for Prandtl number equal to 0.7. Further, typical isotherms, local and mean Nusselt number, velocities and temperature distribution are clarified in detail. The numerical approach presented here appears to be sufficiently versatile to permit computation of a vertical array of cylinders.