Author(s): Jerzy Kolodko
Linked Author(s):
Keywords: No Keywords
Abstract: A simplified, vertically 2-dimensional mathematical model describing the behaviour of river frazil ice is proposed and, by use of some selected examples, its application possibilities are presented. Together with frazil ice the problem of bottom /anchor/ ice is investigated, since both types of ice are considered as two different aspects of the same phenomenon. The most basic assumptions of the model are as follows: - the frazil generation process is assumed to take place just at the water surface, - the well-known turbulent diffusion concept, often used in suspended sediment models, is assumed to be applicable to frazil ice modelling, and finally - the bottom boundary condition is assumed to depend strongly on the state of the frazil crystals /in case of their active state zero concentration is assumed, whereas in case of their passive state the assumption of zero frazil flux is used/. Simple application examples, concerning such topics as: concentration distribution, threshold velocity, bottom ice as well as frazil-caused sediment transport, are given, A new’’rule”, stating that a stable ice-cover does not form where the shear velocity exceeds the buoyancy velocity, is suggested to be the main result of the presented paper.
Year: 1990