Laminar and Turbulent Boundary Layers Adjacent to Melting Vertical Ice Walls in Salt Water.

摘要

A laboratory study of melting vertical ice sheets immersed in sodium chloride solutions of oceanic temperatures and salinities found that the convective motions generated by the melting consist of two regions confined to a boundary layer adjacent to the ice. The first region, at the bottom of the ice, is laminar and bidirectional, with a 2 to 3 mm thick upward flowing layer next to the ice inside of a 10 mm thick outer downward flowing layer. This bidirectionality results from the large difference between the thermal and saline diffusivities which contain dilute water near the ice and allows the cooling to diffuse further from the ice. Near the ice, dilute cold water rises; while away from the ice, cold saline water sinks. Second, further up the ice, the inner layer goes through a region of transition and becomes fully turbulent when the saline Grashof number reaches 2 x 10 to the 8th power. The turubulent flow is upward, unidirectional and the dominant flow in the oceans.