Qualitative and Quantitative Flow Visualization Studies on a Distorted Hydraulic Physical Model

The submergence of coastal wetlands in south Louisiana leaves communities, commerce, industry, and ecosystems vulnerable to extreme weather events and human and natural disasters. The state of Louisiana has developed a plan to mitigate coastal land loss and with the help of Louisiana State University and the Lower Mississippi River Physical Model, projects like large scale sediment diversions will be extensively tested and researched to ensure proper implementation and operation. Due to scaling and distortion of the physical model, complete similitude with its prototype is not expected and scale effects are anticipated to affect the hydrodynamics and, as a result, complete replication of sediment transport dynamics. The objective of this study is to qualitatively and quantitatively observe and analyze the hydrodynamics and hydraulics in a geometrically distorted river model by utilizing two flow visualization techniques - dye injection to investigate the assumption of Reynolds independence and particle image velocimetry (PIV) to investigate the impact of model distortion on 2-dimensional hydrodynamics. The results of the studies effectively answer the questions raised in the objective of this thesis. Dye injection studies show increasing levels of mixing and that 3-dimensional hydrodynamics are observable in the bends of the model river channel. Also, PIV-measured surface velocities show good agreement with theoretical values. These results are intended to help understand the limitations of the physical model so that the model results can be properly applied and, if necessary, modifications to the model can be made to improve the results. This understanding is critical to ensure that the results from this research tool are properly used to aid in river management and coastal restoration planning, design, and policies made by the Louisiana Coastal Protection and Restoration Authority