Traveling wave instability in sustained double‐diffusive convection
| Autor: | Jack Swift, William D. McCormick, Axel G. Rossberg, A. A. Predtechensky, Harry L. Swinney |
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| Rok vydání: | 1994 |
| Předmět: |
Fluid Flow and Transfer Processes
Convection Physics Buoyancy Mechanical Engineering Computational Mechanics Rayleigh number Mechanics engineering.material Condensed Matter Physics Instability Classical mechanics Amplitude Mechanics of Materials engineering Reflection coefficient Scaling Double diffusive convection |
| Zdroj: | Physics of Fluids. 6:3923-3935 |
| ISSN: | 1089-7666 1070-6631 |
| Popis: | Experiments on buoyancy‐driven double‐diffusive convection sustained by imposed vertical concentration gradients (one stabilizing, the other destabilizing) have been conducted in a thin (Hele–Shaw) isothermal rectangular cell. Novel gel‐filled membranes were used to sustain the concentrations at the boundaries. When the destabilizing solute diffuses more rapidly than the stabilizing one, the primary instability leads to traveling waves with a high reflection coefficient at the ends of the cell. The measured critical Rayleigh numbers and frequencies are in reasonable accord with a stability analysis that includes corrections for the finite thickness of the cell and cross‐diffusion effects. The weakly nonlinear waves that appear at onset do not stabilize, even very close to the transition, but continue to evolve, eventually becoming a packet of large amplitude plumes. The packet travels back and forth along the cell in a nearly periodic manner. This behavior and the absence of measurable hysteresis are consistent with the present weakly nonlinear analysis which predicts tricritical scaling (∼e1/4 rather than the usual e1/2) all along the instability boundary. However, the range of this scaling in e was found to be less than 0.005, which is inaccessible in the present experiments. |
| Databáze: | OpenAIRE |
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