AN EXPERIMENTAL-STUDY OF OSCILLATORY CONVECTION IN LIQUID GALLIUM

Results are presented of an experimental study of the onset of time-de pendent flows in a sample of liquid gallium subjected to a horizontal temperature gradient. The primary control parameter is the Grashof num ber which is set by the temperature difference. However, we have also taken the novel approach of varying the Prandtl number in a systematic way using the applied mean temperature. This has uncovered some surpr ising new dynamical states. Furthermore, the interaction between compe ting oscillatory hows has produced interesting dynamical behaviour inc luding secondary Hopf bifurcations where both the frequency and amplit ude grow from zero as the critical point is passed.