摘要
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(分离比ψ=-0.6)的混合流体Un-dulation行进波对流斑图的动力学特性。在相对瑞利数r<6.436时,首次发现一种没有源缺陷的左右相对传播的CPW(Counter propagating waves)状态向行进波状态的过渡形式。在r=6.436—10.8的范围内,发现了两种不同结构的Undulation行进波对流斑图。当6.436<r<10时,出现了腔体内的平均波数在时间上变化且局部波数或当地波数在空间和时间上连续变化的Undulation行进波对流斑图。当r=10—10.8时,出现了腔体内的平均波数在时间上保持为常数而局部波数或当地波数在空间和时间上连续变化的Undulation行进波斑图。在两种状态下,Undulation行进波的摆动周期随瑞利数r增大而减小,它的对流振幅和Nusselt数随瑞利数r增大而增加。在Undulation行进波斑图形成以前,存在以中心为对称的Undulation行进波斑图,它的存活时间依赖于r。当r增加到11.0时,Undulation行进波过渡到定常对流状态。
By using a two dimensional numerical simulation of the fully hydrodynamic equations, the pattern dynamics of the undulation traveling wave convection in binary fluid mixtures with strong Soret effect （the separation ratio ψ = - 0.6） was studied. A transition process to traveling wave convection from counter propagating waves without source defects at the reduced Rayleigh number r〈6. 436 and two type of the patterns of undulation traveling wave convection with different structures in the range of r = 6.436-10.8 were found for the first time. The pattern of undulation traveling wave convection where the mean wave numbers vary with time and the local wave numbers change with time and space at 6. 436 〈r〈10, and the pattern of undulation traveling wave convection where the mean wave numbers keep constant and the local wave numbers change with time and space at 10.0〈r10.8 were also found. In both the two states, the vibration period of the pattern of undulation traveling wave convection decreases with increasing r, the convection amplitude and Nusselt number increase with r. Before the formation of undulation traveling wave convection, a kind of the pattern of undulation traveling wave convection with central symmetry was found and its time of existence depends on r. The undulation travelling wave convection is transition to a stationary overturning convection state at r〉11. 0.
出处
《力学季刊》
CSCD
北大核心
2008年第4期521-529,共9页
Chinese Quarterly of Mechanics
基金
国家自然科学基金项目(10872164)
教育部留学回国人员基金项目(220542)
陕西省教育厅专项计划项目(05JK271)
西安理工大学科研基金项目(210532)
