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We report an experimental study of energy dissipation rate and velocity correlation function and structure functions in turbulent Rayleigh-Bénard (RB) convection with polymer additives in a convection cell with rough top and bottom plates. In a previous study, it was found that the global heat transport is enhanced in this cell when polymer concentration exceeds 120 ppm \cite{PWei2012PRE}. This interesting finding is our motivation for the local velocity measurement. We found that the local energy dissipation rate measured at cell center has similar dependence on polymer concentration as that of the global Nu. It is also found that the energy input from the integral scale is strongly affected by the polymer additives, suggesting an energy pileup near integral scale as a result of the polymer additives. We will discuss the relationship between energy dissipation rate and local heat flux and examine the behavior of velocity longitudinal correlation function and that of velocity structure function.
Author(s):
Ke-Qing Xia
Department of Physics, The Chinese University of Hong Kong
Hong Kong
Rui Ni
Department of Physics, The Chinese University of Hong Kong
Hong Kong
Xiao-Ming Li
Department of Physics, The Chinese University of Hong Kong
Hong Kong
Ping Wei
Department of Physics, The Chinese University of Hong Kong
Hong Kong