两种类型的摆动行波对流

Two types of undulation travelling wave convection

通过流体力学基本方程的数值模拟,研究了摆动(Undulation)行波对流的动力学特性.当分离比ψ=-0.3时,随着r逐渐增加,出现了两种摆动行波对流斑图,即没有固定周期的摆动行波对流和周期性的摆动行波对流。没有固定周期的摆动行波对流,平均波数在k=2.88和k=3.14之间变化,当遇到摆动行波转向时,周期变化的对流振幅的周期破坏,出现对流振幅变化的波动和调整。周期性的摆动行波对流的摆动周期固定,空间平均波数不随时间变化,空间上的局部波数和对流振幅随着时间周期的变化。对不同分离比的研究表明,摆动行波对流的存在区间随分离比绝对值减小而减小,随r增加而减小。比较ψ=0.3的计算结果和其他分离比的计算结果,发现分离比影响着行波对流斑图的形成及它们之间的转化。

Abstract： By using a two-dimensional numerical simulation of the fully hydrodynamic equations, the dynamics of the undulation traveling wave （UTW） convection in two types of UTW convection appear with increasing the a binary fluid mixture was reduced Rayleigh number studied. For the separation ratio ψ=-0.3, r. They are UTW convection without fixedperiod and with fixed period. For the former, mean wavenumbers change between k=2.88 and k=3.14. When the propagating direction of the UTW convection is varied, the period of the convection amplitude which periodically changes is breaked, and the convection amplitude fluctuates and is modulated. For the latter, its vibration period is fixed, and the mean wavenumbers in space do not vary with time. However, the local wavenumbers in space and convection amplitude periodically change with time. For the different separation ratio ψ, the range of existing the UTW convection Ar reduces with decreasing the absolute value of ψ and with increasing r. It is obvious that the ψ has influence on the pattern formation and on the transition between the patterns by comparing the result of ψ= -0.3 with those of differentψ.