OSCILLATORY DOUBLE-DIFFUSIVE CONVECTION IN CRYSTAL-GROWTH

A detailed numerical study of oscillatory convection in a horizontal c ontainer which models crystal growth by the physical vapor transport t echnique has been carried out. The enclosure is subjected to simultane ous horizontal temperature and concentration gradients. The primary go als of this investigation are to predict the critical parameters assoc iated with this phenomena and their influence on the heat and mass tra nsport processes. Our results indicate that the onset of oscillatory m otion occurs at a Grashof number (Gr) of about 10(4) in opposing doubl e diffusive convection. Thus oscillatory convection takes place at a s ignificantly reduced critical Gr compared with the case of pure therma l convection. We also found that boundary fluxes at the interfaces pro mote the onset of oscillation and increase the heat and mass transfer. The effects of different species and enclosure sizes on the critical states are presented.