Date of Award

Spring 2020

Document Type


Degree Name

Doctor of Philosophy (PhD)


Civil & Environmental Engineering


Civil and Environmental Engineering

Committee Director

Gangfeng Ma

Committee Member

Tal Ezer

Committee Member

Gary Schafran

Committee Member

Jaewan Yoon


A common practice in coastal areas is to collect, treat and discharge fluids including treated wastewater, stormwater or power plant effluent to areas of lesser impact. The discharge of these fluids, conveyed through pipelines into coastal areas, continues to be an important human health and environmental concern. The fluid discharged from these pipelines is often buoyant which allows for dilution and dispersion into these ambient waters.

Initial dilution, defined as the maximum concentration of a discharged fluid at the maximum rise in height within a buoyant plume, is critical in the consideration of the environmental impacts of a discharge into receiving waters. The impact of surface gravity water waves on buoyant plumes has been investigated, through a series of experiments to measure both plume size and dilution near the source of discharge. Experimental data has been gathered for surface gravity waves of varying periods and lengths. The volumetric discharge rate of the fluid discharged was also varied to allow for the consideration of various jet densimetric Froude numbers as part of the overall analysis.

Several existing numeric models are in use today to estimate the initial dilution of buoyant plumes. There are also several numeric models in use to understand the impacts of surface waves on the coastal environment. The Non-Hydrostatic Wave (NHWAVE) Model solves the incompressible Navier-Stokes Equations in both terrain and surface to predict coastal wave processes. This model was modified to include a buoyant discharge into an ambient wave environment. The numerical model was calibrated using experimental data to better understand the wave-plume interaction and to predict wave-plume interactions at a large scale.

The research completed as part of this dissertation will provide for a more comprehensive understanding of the initial dilution of buoyant plumes into an environment exposed to regular wave conditions. This understanding can potentially limit the financial, environmental and construction impacts of outfall pipelines in estuary or near-shore ocean environments.


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