具有大负分离比的混合流体局部行进波对流

Localized Travelling Wave Convection in Binary Fluid Mixtures with a Largely Negative Separation Ratio

从流体层底部加热引起的对流运动是研究非平衡对流的时空结构或斑图(Pattern)及非线性动力学特性的典型模型之一。本文通过流体力学基本方程组的数值模拟,探讨了具有强Soret效应的混合流体局部行进波的形成过程,发现当分离比ψ=-0.6时,在局部行进波的存在范围内,向局部行进波过渡的不同过程依赖于相对瑞利数r。进一步,讨论了具有强Soret效应的混合流体局部行进波流速场,温度场,浓度场的结构和特性,分析了局部行进波的存在区间对分离比ψ的依赖性。发现随着Soret效应的增强或负分离比ψ的绝对值的增加,局部行进波稳定存在的区间Δr也在增加。

The convection in a horizontal fluid layer heated from bottom is one of the typical models for studying the spatio-temporal structure（or patterns） and nonlinear dynamics of nonequilibrium convection.By using the numerical simulations of two dimensional full equations of hydrodynamics,the formation process of the localized traveling wave convection was studied in binary fluid mixtures with strong Soret effect,and the different transient processes depend on the reduced Rayleigh number r in the range of existence of the localized traveling wave convection was found for the separation ratio ψ=-0.6.Further,the structures and properties of the vertical velocity,temperature and concentration fields of the localized traveling wave convection in binary fluid mixtures with strong Soret effect were discussed,and the dependence of existence range of the localized traveling wave convection on the separation ratio was analyzed.The results show that the existence range of the localized traveling wave convection increases with Soret effect or the absolute value of the negative separation ratio.