Numerical Simulation of Multiplicity and Stability of Mixed Convection in Rotating Curved Ducts

[摘要] A numerical study is made on the fully developedbifurcation structure and stability of the mixed convection inrotating curved ducts of square cross-section with the emphasis onthe effect of buoyancy force. The rotation can be positive ornegative. The fluid can be heated or cooled. The study reveals therich solution and flow structures and complicated stabilityfeatures. One symmetric and two symmetric/asymmetric solutionbranches are found with seventy five limit points and fourteenbifurcation points. The flows on these branches can be symmetric,asymmetric, 2-cell, and up to 14-cell structures. Dynamicresponses of the multiple solutions to finite random disturbancesare examined by the direct transient computation. It is found thatpossible physically realizable fully developed flows evolve, asthe variation of buoyancy force, from a stable steady multicellstate at a large buoyancy force of cooling to the coexistence ofthree stable steady multicell states, a temporal periodicoscillation state, the coexistence of periodic oscillation andchaotic oscillation, a chaotic temporal oscillation, asubharmonic-bifurcation-driven asymmetric oscillating state, and astable steady 2-cell state at large buoyancy force of heating.

[学科分类] 力学，机械学