极高Ra湍流热对流模拟及其流动特征  

Simulation of turbulent thermal convection and its characteristics at very high Ra

作　　者：罗嘉辉[1] 包芸[1] 

机构地区：[1]中山大学力学系,广州510275

出　　处：《计算机辅助工程》2017年第4期65-70,共6页Computer Aided Engineering

基　　金：国家自然科学基金(11372362;11452002);国家自然科学基金委员会-广东省人民政府联合基金(第二期)超级计算科学应用研究专项(nsfc2015_570)

摘　　要：提出二维湍流热对流DNS模拟的并行直接求解方法(Parallel Direct Method of DNS,PDMDNS),在"天河二号"超级计算机上实现高Ra和极高Ra湍流热对流大规模DNS计算。高分辨率的湍流热对流计算结果表明不同Ra(10~8≤Ra≤10^(13))的瞬时温度场的流场特性完全不同。较低Ra流场中有明显的大尺度环流和角涡;较高Ra流场中羽流运动充满随机性;更高Ra流场出现小尺寸漩涡并不断从上下底板产生,这些涡相互影响作用,随大尺度环流一起作绕行运动。二维湍流热对流的Nu与Ra存在标度关系,标度律约为0.3。A Parallel Direct Method of DNS（ PDM-DNS） for 2D turbulent thermal convection is proposed. The large-scale DNS computation of turbulent thermal convection at high and very high Ra are implemented on Tianhe 2 supercomputer. The high-resolution turbulent thermal convection calculation results show that the flow field characteristics of instantaneous temperature field are utterly different at different Ra（ 10^8≤Ra≤10^13）. The large-scale circulation and corner vortices appear in the flow field at lower Ra. The plume motion is full of randomness in the flow field at the higher Ra. Small vortices appear in the flow fields at high and very high Ra,which are formed at the top and bottom plates continuously. These vortices interact with each other and travel along with the large-scale circulation.There is a scaling rate between Nu and Ra of 2D turbulent thermal convection, which is 0. 3 approximately.

关 键 词：Rayleigh-Bénard热对流 湍流 PDM-DNS 并行计算 极高Ra 羽流形态 

分 类 号：O357.5[理学—流体力学]