Observations of the cell structure of salt fingers

Abstract

The phenomenon of salt fingers has been investigated optically to determine the geometry of the cells as seen from above. When the fingers are short, the flow appears to be highly turbulent, though a dominant scale is evident. When the fingers are longer, a cellular structure is clear. This structure changes only slowly, apparently in response to disturbances in the convecting layers which bound the fingers above and below, and becomes more nearly stationary as the fingers grow. Cell boundaries show a strong tendency to intersect at right angles, which favours the emergence of cells with a square horizontal section. As the fingers get longer the cell width increases, but more slowly than the length.