Modeling Ice-Cover Melting Using a Variable Heat Transfer Coefficient

Abstract

In cold regions, rivers may be partially or completely ice covered during a good part of the year. Under these conditions, heat transfer between the river flow and the atmosphere occurs simultaneously at the ice-air and ice-water interfaces of the ice cover. Heat flux from the water to the ice is the most dominant factor in the growth and decay processes of the river ice. A proper evaluation of the heat transfer coefficient at the ice-water interface is the key for an accurate computation of the heat flux and, consequently, for determining ice-cover melting. A variable heat transfer coefficient for both the entry region and for the fully established flow region was derived. The effects of this coefficient on the computation of ice-cover melting are addressed in this paper through the use of a two-dimensional numerical model. The new approach as well as other constant empirical equations used to evaluate the heat transfer coefficient were respectively used in the model to examine their effects on ice melting. Results of computations using the new approach were in a better overall agreement with experimental observations, including the leading edge region.