transition from steady to oscillatory flow natural convection of low-pr fluids in 3d bridgman configuration for crystal growth

A numerical study of the transition from steady to oscillatory flow natural convection of low- prandtl number fluids inside the 3d bridgman configuration has been carried out. the three-dimensional navier-stokes and energy equations, with the boussinesq approximation have been discretized by means of a finite volume procedure which employs a second order accurate central difference scheme to treat diffusive and convective fluxes. in natural convection, the buoyancy force is only driving the flow and its intensity can be move a harmful effect on the crystal growth, such as the striation. naturally, the steady state flow is obtained for low rayleigh number and shows a great dependence between the rayleigh number, the flow structure and the heat transfer rate. a low increase in the rayleigh number we guide to determine the critical point in which the 3d flow became oscillatory. this regime appears by a sinusoidal signal in the time and developed in each period of time.