Very large-scale structures observed in DNS of turbulent channel flow with passive scalar transport
نویسندگان
چکیده
Direct numerical simulation of a fully developed turbulent channel flow with passive scalar transport has been carried out at four Reynolds numbers, 180, 395, 640 and 1020, based on the friction velocity and the channel half width. The molecular Prandtl numbers are 0.025 and 0.71 where the working fluids are assumed to be mercury and air, respectively. It is shown that for both Prandtl numbers, very large-scale structures of the temperature fluctuations certainly exist in the outer layer at the given Reynolds numbers. Also, it is shown that at high Reynolds number, the very large-scale structures appear hierarchically in the outer layer for the two Prandtl numbers.
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