Turbulent Thermal Convection in an Enclosure With Internal Heat Generation

Abstract

Numerical results are presented for turbulent thermal convection, driven by uniform volumetric energy sources for two-dimensional flows in a rectangular enclosure. Rigid adiabatic sides and a rigid isothermal upper surface are considered. For the rigid bottom surface, zero heat flux boundary conditions are used. Computations are carried out for Prandtl number = 6.5 and Rayleigh number (based on enclosure depth L) range of 106 to 1010. The aspect ratio (L/X) of the enclosure was maintained at 0.5 for all cases. The turbulence model used in this study is a k–ε model, which characterizes turbulence through the kinetic energy and its volumetric rate of dissipation. Buoyancy effects on the turbulence structure are accounted for. Results show the transition from well-ordered multicellular flow to fully turbulent flow within the enclosure as the Rayleigh number increases.