Rayleigh-Bénard convection with phase changes in a Galerkin model.
Rayleigh-Bénard convection with phase changes in a Galerkin model.
复制标题
伽辽金模型中具有相变的瑞利-贝纳德对流。
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
J. Schumacher
中科院分区：
文献类型：
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作者：
T. Weidauer;O. Pauluis;J. Schumacher
在三维Galerkin模型中研究了rayleigh - bsamadard对流相变向湍流的过渡及其对流型。我们的研究重点是湿润对流的条件不稳定状态，在这种状态下，不饱和空气包裹的分层是稳定的，而饱和包裹的分层是不稳定的。我们对向对流的过渡进行了全面的统计分析，对模型相空间中的吸引子（或不动点）对无量纲参数的依赖性进行了采样。条件不稳定对流可以从完全不饱和的线性稳定平衡或完全饱和的线性不稳定平衡开始。高度局部化的湿对流可以在稳定状态、振荡充放电状态或湍流状态下发现，这取决于长径比和不饱和空气的稳定分层程度。我们的相空间分析预测了在亚临界条件不稳定情况下可以观察到的自持续对流状态的参数范围。观测到的湿对流的状态转变与简单剪切流向湍流的转变有一些相似之处。
The transition to turbulence in Rayleigh-Bénard convection with phase changes and the resulting convective patterns are studied in a three-dimensional Galerkin model. Our study is focused on the conditionally unstable regime of moist convection in which the stratification is stable for unsaturated air parcels and unstable for saturated parcels. We perform a comprehensive statistical analysis of the transition to convection that samples the dependence of attractors (or fixed points) in the phase space of the model on the dimensionless parameters. Conditionally unstable convection can be initiated either from a fully unsaturated linearly stable equilibrium or a fully saturated linearly unstable equilibrium. Highly localized moist convection can be found in a steady state, in an oscillating recharge-discharge regime, or turbulent in dependence of the aspect ratio and the degree of stable stratification of the unsaturated air. Our phase-space analysis predicts parameter ranges for which self-sustained convective regimes in the case of subcritical conditional instability can be observed. The observed regime transitions for moist convection bear some similarities to transitions to turbulence in simple shear flows.