scholarly journals Zonal flow reversals in two-dimensional Rayleigh-Bénard convection

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
P. Winchester ◽  
V. Dallas ◽  
P. D. Howell
Keyword(s):  
Zonal Flow ◽  
Two Dimensional ◽  
Bénard Convection ◽  
Benard Convection ◽  
Rayleigh Benard Convection ◽  
Flow Reversals ◽  
Rayleigh Benard

The -dependence of the critical roughness height in two-dimensional turbulent Rayleigh–Bénard convection

2021 ◽  
Vol 911 ◽  
Author(s):  
Jian-Lin Yang ◽  
Yi-Zhao Zhang ◽  
Tian-cheng Jin ◽  
Yu-Hong Dong ◽  
Bo-Fu Wang ◽  
...  
Keyword(s):  
Roughness Height ◽  
Two Dimensional ◽  
Bénard Convection ◽  
Benard Convection ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

Abstract

Flow reversals in Rayleigh–Bénard convection with non-Oberbeck–Boussinesq effects

2016 ◽  
Vol 798 ◽  
pp. 628-642 ◽  
Author(s):  
Shu-Ning Xia ◽  
Zhen-Hua Wan ◽  
Shuang Liu ◽  
Qi Wang ◽  
De-Jun Sun
Keyword(s):  
Large Scale ◽  
Mass Conservation ◽  
Working Fluid ◽  
Large Temperature ◽  
Cold Wall ◽  
Bénard Convection ◽  
Benard Convection ◽  
Rayleigh Benard Convection ◽  
Flow Reversals ◽  
Rayleigh Benard

Flow reversals in two-dimensional Rayleigh–Bénard convection led by non-Oberbeck–Boussinesq (NOB) effects due to large temperature differences are studied by direct numerical simulation. Perfect gas is chosen as the working fluid and the Prandtl number is 0.71 for the reference state. If NOB effects are included, the flow pattern $P_{11}$ with only one dominant roll often becomes unstable by the growth of the cold corner roll, which sometimes results in cession-led flow reversals. By exploiting the vorticity transport equation, it is found that the asymmetries of buoyancy and viscous forces are responsible for the growth of the cold corner roll because both such asymmetries cause an imbalance between the corner rolls and the large-scale circulation (LSC). The buoyancy force near the cold wall increases and decreases near the hot wall originating from the temperature-dependent isobaric thermal expansion coefficient ${\it\alpha}=1/T$ if NOB effects are included. Moreover, the decreased dissipation due to lower viscosity is favourable for the growth of the cold corner roll, while the increased viscosity further suppresses the growth of the hot corner roll. Finally, it is found that the boundary layer near the cold wall plays an important role in the mass transport from LSC to corner rolls subject to mass conservation.

Sign in / Sign up

Export Citation Format

Share Document