具有水平流动的Rayleigh-Bénard对流进口段特性分析  

Characteristics of entrance region in Rayleigh-Bénard convection with horizontal flow

作　　者：宁利中[1] 张迪[1] 宁碧波[2] 胡彪 田伟利[4] Ning Lizhong;Zhang Di;Ning Bibo;Hu Biao;Tian Weili(State Key Laboratory of Eco-hydraulies in Northwest Arid Region,Xi an University of Technology,710048,Xi'an,China;College of Civil Engineering and Architeeture,Jiaxing University,314001,Jiaxing,China;Jiangxi Provincial Design&Research Institute of Water Conservancy&Hydropower,330029,Nanchang,China;Department of Architecrure,Shanghai University,204444 Shanghai,China)

机构地区：[1]西安理工大学省部共建西北旱区生态水利国家重点实验室,西安710048 [2]嘉兴学院建筑工程学院,嘉兴314001 [3]江西省水利规划设计研究院,南昌330029 [4]上海大学建筑学院,上海200444

出　　处：《应用力学学报》2020年第3期1260-1265,I0024,I0025,共8页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金项目(10872164);西北旱区生态水利国家重点实验室基金项目(2017ZZKT-2)。

摘　　要：采用SIMPLE算法对二维流体力学基本方程组进行了数值模拟,对普朗特数Pr=0.0272的具有水平流动的Rayleigh-Bénard对流进口段特性进行了研究。结果表明,在某些流体参数下具有水平流动的Rayleigh-Bénard对流由进口段和行波对流段组成,进口段长度取决于雷诺数和相对瑞利数。对于雷诺数Re=150的情况,当相对瑞利数r≤4时腔体内是水平流动;当r≥12时腔体内是行波对流;在4<r<12范围内,存在进口段,并提出了进口段长度X0随着相对瑞利数变化的表达式。对于相对瑞利数r=3的情况,当雷诺数Re≤37.5时腔体中是行波对流;当雷诺数Re≥110时腔体中是水平流动;在37.5≤Re≤110范围内,存在进口段,并获得了进口段长度X0随着雷诺数变化的表达式。进口段长度随相对瑞利数的增大而减小,随着雷诺数的增大而增大。行波对流区的对流波数随着雷诺数的增大而减小。The SIMPLE algorithm is used to numerically simulate the two-dimensional basic equations of fluid mechanics,and the characteristics of entrance region in the Rayleigh-Bénard convection with horizontal flows of the Prandtl number Pr=0.0272 are studied.The results show that the Rayleigh-Bénard convection with horizontal flow is composed of entrance region and traveling wave convection region under appropriate fluid parameters.The length of the entrance region depends on the Reynolds number and the reduced Rayleigh number.For Reynolds number Re=150,the horizontal flow occurs in the cavity at reduced Rayleigh number r≤4,and traveling wave convection occurs in the cavity at r≥12.The entrance region appears in the range of 4<r<12,and the expression of the length of the entrance region varying with reduced Rayleigh number is suggested.For reduced Rayleigh number r=3,the traveling wave convection occurs in the cavity at Re≤37.5,and the horizontal flow occurs in the cavity at Re≥110.The entrance region exists in the range of 37.5≤Re≤110,and the formula of the length of the entrance region with the variation of Reynolds number is obtained.The length of the entrance region decreases with the increase of the reduced Rayleigh number and increases with the increase of the Reynolds number.The convective wave number in the traveling wave convection region decreases with the increase of Reynolds number.

关 键 词：水平流动 Rayleigh-Bénard对流 进口段 相对瑞利数 雷诺数 

分 类 号：O357[理学—流体力学]