NUMERICAL-SIMULATION OF 2-DIMENSIONAL BUOYANCY-DRIVEN TURBULENCE IN ATALL RECTANGULAR CAVITY

A computational study of natural convection of air in a tall rectangul ar cavity with 4:1 aspect ratio is conducted. In an effort to investig ate the applicability of the Boussinesq approximation to turbulent flo w simulation, the cavity is differentially heated from the sides and i s insulated at the ends at a Rayleigh number of 10(9). Starting from q uiescent and isothermal flow conditions, the flow is driven to turbule nce without any artificial perturbations. The computer programme devel oped integrates the two-dimensional, time-dependent Navier-Stokes equa tions with the Boussinesq approximation and the energy equation by a t ime-accurate method on a stretched, staggered grid. The simulation pro ceeds to a statistically steady solution in which large-scale structur es are found in the mean. Both mean and fluctuating quantities provide good agreement with experimental results.