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

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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.