NUMERICAL STUDY OF THE LAMINAR NATURAL-CONVECTION FLOW AROUND HORIZONTAL ISOTHERMAL CYLINDER

Natural convection around a horizontal circular cylinder under constan t temperature or constant heat flux conditions in an infinite space ha s been the subject of numerous investigations in recent years. However , these studies use the inflow-outflow boundary in cylindrical coordin ates that gives a sensible error, especially when the Rayleigh number is small. This investigation, that enters within the framework of gene ral study dealing with natural convection from an array of cylinders, states the problem in cartesian coordinates system, involves the use o f a control-volume method and resolves various apparent redundancies i n boundary conditions. This problem was investigated numerically for l aminar case by solving the full vorticity transport equation together with the stream function and energy equations. Results are obtained fo r 10(1) < Ra < 10(6) and for Prandtl number equal to 0.7. Further, typ ical isotherms, local and mean Nusselt number, velocities and temperat ure distribution are clarified in detail. The numerical approach prese nted here appears to be sufficiently versatile to permit computation o f a vertical array of cylinders. (C) 1998 Elsevier Science Ltd.