混合流体Rayleigh-Benard行波对流中的缺陷结构

通过流体力学基本方程的数值模拟，研究了含有缺陷的行波对流的动力学特性. 当分离比Ψ＝－06时，随着相对瑞利数r逐渐增加，系统由局部行波对流过渡到含有缺陷的行波对流，然后缺陷消失过渡到无缺陷的行波对流. 对于不同分离比的研究表明，缺陷出现的周期随着分离比减小而迅速增加，随着r增加而增加. 在负的小分离比时的增加速率大于大分离比时的增加速率. 缺陷存在区间Δr随着分离比绝对值减小很快变小, 并且当Ψ＝－011时缺陷消失，没有发现含有缺陷的行波对流. 当r大于Δr的上限时，系统过渡到无缺陷的行波对流.可是，当r小于Δr的下限时，不同的分离比Ψ值，对应不同的行波对流斑图. 这说明分离比明显地影响着各斑图形成及它们之间的转换，斑图之间的转换是很复杂的. 关键词： Rayleigh-Benard对流 缺陷 混合流体 行波

Defect structures of Rayleigh-Benard travelling wave convection in binary fluid mixtures

By using a two dimensional numerical simulation of the fully hydrodynamic equations, the dynamics of the traveling wave convection in binary fluid mixtures with defects was studied. For the separation ratio Ψ=-06, the system changes from localized traveling wave to traveling wave （TW） convection with the defects with increasing reduced Rayleigh number r. Then, the defects disappear and it changes to TW without defects with further increasing r. For different separation ratio Ψ, the periodicity of appearance of defects increases with reducing separation ratio and increasing r. The increase rate for a small negative separation ratio is larger than that for separation ratios. The range of existence of defects Δr remarkably decreases with the absolute value of Ψ. At Ψ=-011, the defects are annihilated and the TW with defects is not found. The system turns to the TW without defects from the TW with defects where r is larger than the upper limit of Δr. However, different values of Ψ correspond to different TW patterns when r is less than the lower limit of Δr. Therefore, it is obvious that the Ψ has influence on the pattern formation and on the transition between the patterns, and the transition between the patterns is also complex.