局部行波对流的时空结构  

Spatiotemporal structures of localized traveling wave convection

作　　者：宁利中[1] 宁碧波[2] 王新宏[1] 袁喆[1] 田伟利[3] 

机构地区：[1]西安理工大学西北旱区生态水利工程国家重点实验室培育基地,西安710048 [2]嘉兴学院建筑工程学院,嘉兴314001 [3]上海大学建筑系,上海200444

出　　处：《应用力学学报》2018年第5期996-1001,共6页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(10872164);西北旱区生态水利工程国家重点实验室培育基地基金(2017ZZKT-2)

摘　　要：通过流体力学方程的数值模拟,研究了矩形腔体长高比Γ(28)20和混合流体分离比ψ(28)-0.4的无缺陷的局部行波对流和有缺陷的局部行波对流的特性。结果表明:局部行波可以存在于腔体左端壁附近,也可以存在于右端壁附近,但传播方向始终在背离端壁面的方向,对流存在区间长度随着相对瑞利数r的增加而增加;沿着对流分叉曲线增加r,当r超过临界值后,系统从无缺陷的局部行波过渡到有缺陷的局部行波状态;对于流体参数,无缺陷的局部行波存在于r∈[1.519,1.600],有缺陷的局部行波存在于r∈(1.600,1.670];有缺陷的局部行波中对流区间长度随着r增加基本保持为常数;缺陷出现在腔体中的相对位置基本不变,距背离传播方向的端壁5.8左右,缺陷出现的周期随着r增加呈增加趋势,腔体的长高比足够大是出现有缺陷的局部行波的一个必要条件。In this paper, the numerical simulations are made by solving the two-dimensional full equations of hydrodynamics, the characteristics of the localized traveling wave convection with and without defects in the rectangular cavity with the aspect ratio Г=20 and in binary fluid mixture with the separation ratio ψ=-0.4 are studied. It is found that the localized traveling wave can be located near the left end of the cavity or near the right end wall, but the traveling wave always propagates in the direction deviating from the end wall and the interval length of convection increases with the increase of reduced Rayleigh number r. With increasing r along the convective bifurcation curve, the system is transformed from the localized traveling wave without defects to the localized traveling wave with defects when the critical value of r is exceeded. For the fluid parameters in this paper, the localized traveling wave without defects exists in r ?[1.519,1.600] and the localized traveling wave with defects exists in r ?[1.600,1.670]. In the localized traveling wave with defects, the interval length of the convection is kept constant with the increase of r,and the relative position of the defect in the cavity is almost the same, which is about 5.8 leaving the end wall deviating from the direction of propagation. The period of defects increases with increasing r. A necessary condition for the existence of localized traveling wave with defects is that the rectangular cavity must possess the large aspect ratio.

关 键 词：局部行波 缺陷 周期 数值模拟 

分 类 号：O357[理学—流体力学]