Flow Pattern of Thermal Convection of Boussinesq Fluid with Phase Change of Water

研究了含有气液相变物质的Boussinesq流体的热对流问题。气-液相变本质上是流体的内热收支，同时也使物质的量通过“蒸发”而减少。但在本研究中，我们把注意力集中在相变的第一个方面。我们制定了一个最简单的形式的系统，并进行参数调查的潜热和相变的特征时间，在超临界状态的Benard对流，在其中的二维角色对流是稳定的和稳定的。数值研究表明，随着相变特征时间的减小，对流胞尺寸先增大后减小。潜热的增加被发现支持这种变化的细胞大小。通过稳定性分析证实了泡孔尺寸的变化。本文还研究了地球物理条件下的湿对流流型、旋转球壳中热对流与磁场的相互作用以及旋转球上的二维流型。

Thermal convection is studied for Boussinesq fluid which including a material which undergoes a phase change between gas and liquid. The gas-liquid phase change in nature acts as an internal heat budget of the fluid, and simultaneously makes the amount of the material decrease through 'rainfall'. But in this study we focus our attention on the first aspect of the phase-change. We formulate the system in a simplest form, and perform a parameter-survey for the latent heat and a characteristic time of the phase change, in a supercritical state of Benard convection, in where two-dimensional role convection is steady and stable. Numerical study shows that as the characteristic time of the phase change decreases, the convection-cell size first becomes larger and then turns to decrease. The increase of the latent heat is found to support this variation of the cell-size. The variation of the cell size is confirmed by stability analysis. The flow pattern of moist convection in geophysical situation, the interaction of thermal convection in a rotating spherical shell with magnetic field, and two-dimensional flow patterns on a rotating sphere are also studied.