Effects of Ambient Crossflows and Density Stratification of the Characteristic Behavior of Round, Turbulent Buoyant Jets

Author: Wright, Steven Jay

Year: 1977

Degree: Dissertation (Ph.D.)

Advisor: Brooks, Norman H.

Committee Member: Unknown, Unknown

Option: Civil Engineering

DOI: 10.7907/424v-vn63

Abstract

This investigation considers a round, turbulent buoyant jet in an ambient crossflow that is either of uniform density or with a linear density stratification. The primary emphasis is the development of a fundamental understanding of the jet properties that are of interest in engineering design problems. These include jet trajectories, characteristic dilutions, and in the case of a stratified crossflow, the maximum and equilibrium heights of rise.

Most previous studies of similar buoyant jet flows have used the integral method to solve for the jet characteristics. This approach requires an assumed relation for the rate of entrainment of ambient fluid by the jet, and also depends upon experimental evidence to estimate values for the coefficients in the assumed relation. Most previous experimental studies have been directed toward evaluating entrainment coefficients and have not considered a systematic investigation of the effects of the various jet and ambient flow parameters.

A major objective of this investigation is to provide a basis for the interpretation and extension of the results from previous theoretical and experimental investigations. A systematic dimensional analysis is performed to define the basic problem and to provide approximate solutions without using the integral equations. The analysis indicates the types of experiments necessary to adequately describe general buoyant jet behavior and also provides a framework for the presentation of experimental data.

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