Effects of Water Temperature and Salt Concentration on the Characteristics of Horizontal Buoyant Submerged Jets

Abstract

This paper summarizes the results of an analytical/experimental study of submerged buoyant fresh water and salt water jets injected horizontally into a quiescent, unstratified reservoir. Fresh water jets of a fixed exit Froude number penetrated to a greater horizontal distance before surfacing as the temperature of the reservoir was lowered. The overall flow characteristics were markedly affected by changes in the reservoir temperature, but were only slightly dependent upon the jet exit temperature for a given reservoir. Salt water jets of a fixed exit Froude number penetrated shorter horizontal distances into the reservoir as the salt concentration was increased. An analytical model was developed for fresh water jets which includes the effect of temperature on the thermal expansion coefficient and the effective buoyancy of the jet. The model successfully predicts the observed temperature dependence in the experiments and is applicable to salt water jets at low concentration levels. A correlation is proposed to minimize the effect of the reservoir temperature on the jet trajectory. The dependence of the flow characteristics on temperature and salt concentration is shown to be a significant factor contributing to the wide discrepancy in the data reported by previous investigators.