Author(s): Gerald A. Schohl; Robert Ettema
Keywords: No Keywords
Abstract: Naled ice growth and the key parameters influencing it are described, using the results of conservation-principle formulations, dimensional analysis and laboratory experiments conducted with a refrigerated flume. Naleds are also known as aufeis or icings. The growth of a two-dimensional, or laterally confined (flume), naled can be described using seven Independent, normalized parameters. The early phase of naled ice growth depends on only four of the seven parameters. During this phase of growth, a naled consists of a mixture of ice and water, or ice-water slush, forming on a frigid base. The Influences of two of the three remaining parameters are not felt until the ice-water slush begins freezing over to form a lamination of ice, whereupon a new slush layer forms. The continuing, cyclic process by which slush layers form and eventually freeze results in the ice laminations that characterize naleds. The influence of the seventh governing parameter, a Reynolds number, cannot be discerned in the laboratory data. A useful equilibrium-length concept is introduced as a scale for describing naled ice growth. This conceptual length scale is derived from the balance of water discharge to a naled and the rate with which naled ice grows.