Submerged warm water jet discharge in an ice-covered reservoir or lake

Abstract

A submerged warm water jet discharge into an ice-covered lake or reservoir is investigated by one-dimensional and two-dimensional flow and heat transfer simulation. A one-dimensional jet integral model combined with a one-dimensional, unsteady heat transfer model for a natural lake is used to predict jet trajectories and vertical temperature distributions in the receiving water under an ice cover. A two-dimensional and unsteady flow and temperature simulation is made by solving the Reynolds equations with a buoyancy-modified κ-ϵ model for closure. The results of both 1-D and 2-D simulations show the great significance of buoyancy effects on the jets. The progressive mixing and warming of the initially stratified (0° to 4°C) ambient water are illustrated. Feedback from changing ambient conditions changes buoyancy forces acting on the jet dramatically. Buoyancy reversal is illustrated for jets discharged at initial temperatures from 8° to 15°C, as the jets become diluted by entrainment of colder ambient water. Ice covers are affected by this reversal. Jet discharge temperature and ambient water depletion are shown to be the most important factors controlling the behavior of submerged water jet discharges into ice-covered reservoirs or lakes.