Author(s): R. G. Saade; S. Sarraf; G. Holder
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Keywords: No Keywords
Abstract: During winter, rivers and channels in northern countries are partially or completely ice covered. This natural phenomenon is of great concern to engineers since it causes problems related to navigation, hydraulic structures, municipal and industrial waste disposal and flood mitigation. Increases in the water temperature resulting from the discharge of waste heat may result in melting of ice cover or even its complete suppression. The process of melting of floating ice cover is dependent on the turbulent flow characteristics, and the heat flux across the ice cover interfaces which in turn are a function of the hydrothermal characteristics of the river and the prevailing meteorological conditions. A two-dimensional turbulence model coupled with an ice cover melting model was used to investigate the influence of air and water temperature on the melting characteristics of an ice cover. Flow parameters are determined using the St. Venant shallow water equations taking into account the effect of ice cover on flow regime. The unsteady two-dimensional energy equation is used to obtain the temperature field. Changes in ice thickness is obtained from the use of heat transfer equations at the water-ice, and ice-air interfaces. The upwind finite-difference scheme is applied to the transport equations, while a modified version of the MacCormack scheme is used to discretize the hydrodynamic equations. Three test cases were considered such that air and water temperatures were varied to investigate their influence on the ice cover melting characteristics. The results of the model simulation are presented in comparison to laboratory experiments. These results show that the influence of water temperature variation on the extent of ice cover melting is significantly higher than these of air temperature. Numerical computations of ice cover melting patterns showed good accordance with laboratory measurements.
Year: 1992