不同Pr数湍流热对流流动特征  

Flow characteristics of turbulent convection with different Prandtl numbers

作　　者：叶孟翔 包芸[1] 

机构地区：[1]中山大学应用力学与工程系,广州510275

出　　处：《水动力学研究与进展（A辑）》2017年第4期463-469,共7页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金(11372362;11452002)~~

摘　　要：该文采用高效并行PDM-DNS方法,计算了10~8≤Ra≤10^(10),Pr=0.7和4.3的二维湍流热对流。相同Ra数情况下,两种Pr数下的羽流形状及运动存在明显差异,Pr=0.7时羽流结构更不稳定,同时大尺度环流路径的尺寸在Pr=0.7时也较小;两个Pr数的平均场有基本相同的温度边界层厚度,系统的传热效率Nu数基本相等;比较水平速度的纵向分布,Pr=0.7时水平速度的最大值较大,出现的位置距上下边界较远。A numerical study from the parallel direct method of direct numerical simulation （PDM-DNS） for two dimensional Rayleigh-Brnard convection was carried out, where we varied the Rayleigh number between 10^8≤ Ra 〈 10^10 ,with Prandtl number 0.7 and 4.3. With the constant value of Rayleigh number, the shape and motion of plume are different between Prandtl number 0.7 and 4.3. For Pr=0.7, the stucture of plume is instable, with the smaller size of Large Scale Circulation（LSC）. The thickness of thermal boundary and Nusslt number are the same for both Prandtl number 0.7 and 4.3. Comparing the horizontal velocity distribution, we found the maxium of horizontal velocity is greater in Prandtl number 0.7 rather than in 4.3, also more far away from both the top and bottom plate.

关 键 词：Rayleigh-Benard热对流 PDM-DNS PR数 羽流 大尺度环流 

分 类 号：O357.5[理学—流体力学]