SALT FINGERS AND CONVECTING LAYERS

It is shown that convective 'fingers' can form not only in the salt-heat system, but also in a fluid containing two solutes with much closer diffusivities (for example sugar above a salt solution). This experimental device is used to explore various phenomena which cannot easily be produced in the laboratory with salt and heat. We have investigated: (a) the behaviour of an interface containing fingers and separating two convecting layers, (b) the production of a series of steps from a smooth gradients by imposing a flux at the top, (c) and the mechanism of formation of layers from two opossing gradient bof the solutes. In each case the related theoretical ideas are summarized, and it is suggested how these can be extended to describe the new features of the observations. © 1969.