Laminar free convection in confined regions
Laminar free convection in confined regions
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有限区域内的层流自由对流
DOI：
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发表时间：
1985
影响因子：
3.7
通讯作者：
Alison M. Leitchs
中科院分区：
文献类型：
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作者：
B. M. G. WORSTERt;Alison M. Leitchs
我们研究了由于浮力源产生垂直对流边界层而在受限流体中密度分层的发展。我们发现当边界层是层流而不是湍流时，分层显着不同。特别地，流体内部的密度梯度的大小沿着边界层的流动方向增加而不是减小，并且该密度梯度平滑地变化，使得分层流体和未改性的均质流体之间不存在密度前沿。描述了实验室实验，其中矩形容器中的均匀流体在垂直侧壁处被加热。拍摄了垂直温度剖面和条纹照片，显示了层流条件下分层机制的主要特征。我们回顾了均匀环境中垂直、层流、自由对流边界层的相似理论，并为分层环境中的对流边界层开发了新的相似解决方案。我们使用这些分析结果来解释实验观察到的流场的定性特征，并开发分层深度随时间变化的表达式。
We investigate the development of density stratification in a confined fluid due to a buoyancy source which gives rise to a vertical convective boundary layer. We find that the stratification is significantly different when the boundary layer is laminar rather than turbulent. In particular, the magnitude of the density gradient in the fluid interior increases rather than decreases in the direction of flow of the boundary layer, and this density gradient varies smoothly so that there is no density front between the stratified fluid and the unmodified homogeneous fluid. Laboratory experiments are described in which homogeneous fluid in a rectangular container was heated at a vertical sidewall. Vertical temperature profiles and streak photographs were taken which show the dominant features of the stratification mechanism under laminar flow conditions. We review similarity theory for a vertical, laminar, free-convection boundary layer in a homogeneous environment, and develop new similarity solutions for convective boundary layers in stratified environments. We use these analytic results to interpret qualitative features of the experimentally observed flow fields and to develop an expression for the depth of the stratified layer as a function of time.