摘要
水平来流和上下壁温度差的热作用使腔体内的流体发生运动,腔体内会呈现精彩的对流斑图。该文采用二维流体力学基本方程组的数值模拟,研究了普朗特数Pr=6.99时矩形腔体外加水平来流对局部行波对流结构的影响。由水平来流和垂直热作用的相互作用可获得均匀行波,局部行波和水平流三种对流斑图。在保持相对瑞利数r不变,水平来流雷诺数Re逐渐增大的情况下,可以得到均匀行波转变到局部行波的水平来流临界雷诺数Re,即局部行波存在的下临界雷诺数Re_l;局部行波转变到水平流的水平来流临界雷诺数Re,即局部行波存在的上临界雷诺数Re_u。通过改变相对瑞利数r发现了不同的水平来流临界雷诺数Re_l,Re_u。发现水平来流临界雷诺数随相对瑞利数r增大而增大;并给出了水平来流临界雷诺数Re_l,Re_u与相对瑞利数的函数关系式。同时对局部行波的结构进行了分析,可得局部行波的宽度随水平来流雷诺数的增大而减小。
Horizontal flow and the thermal effect caused by the temperature difference between the upper and lower walls make fluid move, a wonderful convective pattern will present in the cavity. By using a two-dimensional numerical simulation of the fully hydrodynamic equations, the convection structure of localized traveling wave with horizontal flow in a rectangular channel at Prandtl number Pr = 6.99 is studied. Three types of convection patterns, such as traveling wave, localized traveling wave and horizontal flow, are obtained by the interaction of horizontal flow and vertical thermal effect. If the reduced Rayleigh number r is kept constant, and the Reynolds number Re is increased, the lower critical Reynolds number Ret of transition to the localized traveling wave from the traveling wave and the upper critical Reynolds number Reu of transition to horizontal flow from the localized traveling wave are aquired. By changing the reduced Rayleigh number r, the different critical Reynolds numbers Rel , Ret are found. And the results show that the critical Reynolds numbers Rel , Re increases with the increase of reduced Rayleigh number r ; and formulas on variation of the critical Reynolds number with the reduced Rayleigh number r are given. In this paper, the structure of localized traveling wave is analyzed, and the width of the localized traveling wave decreases with the increase of Reynolds number.
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2017年第1期110-116,共7页
Chinese Journal of Hydrodynamics
基金
国家自然科学基金项目(10872164)
陕西省重点学科建设专项资金资助项目(00X901)~~
