CAREER: Advancing Nearshore Circulation Modeling

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ABSTRACTPI/Institution: Slinn/UF-G Proposal No: OCE-0239642 This integrated plan for research and education in Coastal Engineering will emphasize nearshore circulation modeling. Two new (three-dimensional (3-D), time-dependent, non-hydrostatic, large-eddy simulation (LES) surf zone models will be used to gain improved understanding of effects of three important nearshore processes: 1) Mean undertow; 2) Along-shore current instabilities; and 3) Partitioning of offshore mass transport between rip currents and undertow. Calibration of the models will be achieved by comparison with laboratory measurements collected at the Army Corps of Engineers, Long-Shore Sediment Transport Facility (LSTF) and with data from recent and ongoing field experiments at Duck, North Carolina, Daytona Beach, Florida, and from planned experiments such as NCEX. Six specific hypotheses will be tested with the models, lab, and field data. The first new model is a phase-averaged model and examines the depth-dependent, low-frequency, nearshore current response to breaking waves in the surf zone. This model is faster computationally than other similar codes and can be used to study shear instabilities of the mean current and time-averaged effects of the undertow in unsteady flows. The second new model is based on the Volume of Fluid (VOF) algorithm and simulates the individual wave breaking events in the surf zone within the LES approximations. This model can be used to examine individual wave-breaking effects but it is slower computationally, because of the more complex methodology for solving the Poisson equation and because smaller time steps are required to capture higher frequency fluctuations associated with turbulent flow caused by breaking waves. It is anticipated these new models will help the field converge towards improved predictive capabilities for near shore flow. Five specific educational integration activities are described. These include: 1) guiding graduate students on their thesis projects; 2) supervising senior projects for Civil Engineering students, 3) developing a new under-graduate course introducing Coastal Engineering to Civil Engineering majors; 4) collaborating with students from outside of engineering on nearshore science and public information projects, and 5) enhancing my own continuing education by taking (and then teaching) advanced courses in Coastal Engineering.