Turbulent Rayleigh-Bénard Convection in Air: How Uniform Is the Local Wall Heat Flux at Finite Aspect Ratio?

Abstract

In our talk we present a visualization of the flow field inside the boundary layer in highly turbulent Rayleigh-Bénard convection in air. Sequences were captured at various positions along the heated bottom plate in a rectangular cell of 2.5×2.5×0.6 m3 at a Rayleigh number of Ra = 1.3×1010. They demonstrate that the velocity field may not be considered as uniform over the entire surface of the plate and, therefore, the distribution of the local heat flux becomes non-uniform as well. Local heat flux measurements using an infrared camera show that in the specific case this quantity varies by at least ±10% depending on the local flow condition at distinct areas of the plate surface.KeywordsRayleigh NumberLocal HeatInfrared CameraHeating PlateSmall Aspect RatioThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.