Wave Propagation in Ice‐Covered Channels

Abstract

The propagation of waves in ice‐covered channels is analyzed using linearized forms of the three equations governing one‐dimensional unsteady flow in rectangular ice‐covered channels. The equations describe fluid continuity, momentum, and the ice‐cover response. The ice cover is assumed to be a relatively thin, continuous elastic plate. Five well‐defined bands of wave celerity are found in the wave‐number spectrum. Three bands exist at wavelengths longer than about 20 characteristic lengths of the ice and define the range of quasi‐open‐channel wave propagation over which the wave celerities are analogous to open‐channel wave celerities. Two bands exist at shorter wavelengths: an ice‐coupled band (in which the wave celerity increases sharply with wave number and is a function of the wavelength and the ice‐cover properties) and, at even shorter wavelengths, an acoustic band. The attenuation of ice‐coupled and acoustic waves is found to be small. The group velocity over the dispersive ice‐coupled band is found to always exceed the wave celerities.