2015/01/08 by Erwin P. van der Poel, van der Poel, Erwin P., Rodolfo Ostilla–Mónico +5
Computer Science · Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Nanofluid Flow and Heat Transfer #Nonlinear Dynamics and Pattern Formation
paper · pdf · doi:10.48550/arxiv.1501.01837
openalex publication_date 2015/01/08 · openalex created_date 2022/10/03 · openalex updated_date 2026/07/28
The effect of various velocity boundary condition is studied in\ntwo-dimensional Rayleigh-B 'enard convection. Combinations of no-slip,\nstress-free and periodic boundary conditions are used on both the sidewalls and\nthe horizontal plates. For the studied Rayleigh numbers Ra between 108 and\n1011 the heat transport is lower for \Γ = 0.33 than for \Γ = 1\nin case of no-slip sidewalls. This is surprisingly opposite for stress-free\nsidewalls, where the heat transport increases for lower aspect-ratio. In wider\ncells the aspect-ratio dependence is observed to disappear for \Ra \≥\n1010. Two distinct flow types with very different dynamics can be seen,\nmostly dependent on the plate velocity boundary condition, namely roll-like\nflow and horizontal zonal flow, which have a substantial effect on the dynamics\nand heat transport in the system. The predominantly horizontal zonal flow\nsuppresses heat flux and is observed for stress-free and asymmetric plates. Low\naspect-ratio periodic sidewall simulations with a no-slip boundary condition on\nthe plates also exhibit zonal flow. In all the other cases, the flow is\nroll-like. In two-dimensional Rayleigh-B 'enard convection, the velocity\nboundary conditions thus have large implications on both roll-like and zonal\nflow that have to be taken into consideration before the boundary conditions\nare imposed.\n