Transitions and chaos in natural convection of a fluid with Pr=0.1 in a horizontal annulus

Bifurcation sequence to chaos in natural convection in a horizontal annulus is numerically investigated for the fluid of Pr = 0.1. As Ra is increased, a transition from a steady unicellular flow to an oscillatory multicellula r flow with a counter-rotating eddy on the top of the annulus occurs. After the first Hopf bifurcation from steady to monoperiodic flow, a period-3 so lution first appears. Quasi-periodic flow and two period-doubling bifurcati ons are recorded before chaos, and a window of period 4 is observed between chaotic states. (C) 2000 The Japan Society of Fluid Mechanics and Elsevier Science B.V. All rights reserved.