LAMINAR NATURAL-CONVECTION IN A LATERALLY HEATED AND UPPER COOLED VERTICAL CYLINDRICAL ENCLOSURE

Numerical simulation of laminar natural convection in a Vertical cylin der is proposed. The cylinder is insulated at the bottom, laterally he ated at a uniform heat flux density and cooled at the same flux at the top surface. The influence of the characteristic parameters of the pr oblem on the steady-state solution is analysed (10(2) less than or equ al to Ra less than or equal to 10(6); 0.7 less than or equal to Pr les s than or equal to 92.5; 1/5 less than or equal to Al less than or equ al to 2). The fluid transient behaviour is also investigated. It is fo und that the stationary convective heat transfer is more important at the top surface for 1/5 less than or equal to Al less than or equal to 1/2 and is explicitly independent of the Prandtl number. The steady-s tate Bow presents a single roil pattern in all cases. On the other han d, in the transient phase a time-limited two-roll flow is predicted wh en Al less than or equal to 1/3. (C) 1998 Elsevier Science Ltd. All ri ghts reserved.