A numerical study is carried out for the two-dimensional time-dependent turbulent free convection in an open square cavity with a heated back wall and insulated top and bottom walls. The flow medium is air. With the Low-Reynolds-Number k-s turbulence model, the perfect gas law and the extended computational domain method accepted, calculations have been done for Rayleigh numbers up to 1011. The evolution in time of velocity, temperature, turbulent kinetic energy, and the local and averaged Nusselt numbers are given and discussed. It is shown that the unsteady free convection progress in an open cavity is rather complex and can be altered some due to the changing of the Rayleigh numbers.
