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キーワード:
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要旨:
Many environmental flows arise due to natural convection at a vertical surface, from
flows in buildings to dissolving ice faces at marine-terminating glaciers. We use
three-dimensional direct numerical simulations of a vertical channel with differentially
heated walls to investigate such convective, turbulent boundary layers. Through the
implementation of a multiple-resolution technique, we are able to perform simulations at a
wide range of Prandtl numbers Pr. This allows us to distinguish the parameter dependences
of the horizontal heat flux and the boundary layer widths in terms of the Rayleigh
number Ra and Prandtl number Pr. For the considered parameter range 1 ≤ Pr ≤ 100,
106 ≤ Ra ≤ 109, we find the flow to be consistent with a ‘buoyancy-controlled’ regime
where the heat flux is independent of the wall separation. For given Pr, the heat flux is
found to scale linearly with the friction velocity V∗. Finally, we discuss the implications of
our results for the parameterisation of heat and salt fluxes at vertical ice–ocean interfaces.
