title: Local energy dissipation rate balances local heat flux in the center of turbulent thermal convection.
abstract: The local kinetic energy dissipation rate ε(u,c) in Rayleigh-Bénard convection cell was measured experimentally using the particle tracking velocimetry method, with varying Rayleigh number Ra, Prandtl number Pr, and cell height H. It is found that ε(u,c)/(κ(3)H(-4))=1.05×10(-4)Ra(1.55±0.02)Pr(1.15±0.38). The Ra and H dependencies of the measured results are found to be consistent with the assumption made for the bulk energy dissipation rate ε(u,bulk) in the Grossmann-Lohse model. A remarkable finding of the study is that ε(u,c) balances the directly measured local Nusselt number Nu(c) in the cell center, not only scalingwise but also in magnitude.
authors: Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors: Rui
authors: R
authors: Ni
authors: Shi-Di
authors: SD
authors: Huang
authors: Ke-Qing
authors: KQ
authors: Xia