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Timothy R. Nelson, Ph.D.

Timothy R. Nelson, Ph.D.
Project Scientist

Timothy R. Nelson, Ph.D.

Project Scientist

Dr. Timothy Nelson is an oceanographer with 8 years of experience researching sediment dynamics and coastal geomorphology. His research efforts have focused on quantifying the temporal and spatial evolution of bedforms, sediment resuspension, and nearbed turbulence. He has studied sediment transport in relation to the mobility of low-density gravel to cobble sized sand and oil agglomerates following oil spills. Dr. Nelson’s research has also focused on barrier island response, recovery, and resiliency to abrupt changes in morphology, and the development of automated routines to quantify long-term shoreline change.

Projected Cross-Shore Changes in Upwelling Induced by Offshore Wind Farm Development Along the California Coast

Publication

April 13 2023

Effect of Floating Offshore Wind Turbines on Atmospheric Circulation in California

Publication

June 01 2022

Advancing Renewable Energy: Integral Awarded Funding from DOE for Open-Water R&D at PacWave

Press Release

April 15 2022

Coastal Geomorphology

Quantifying Barrier Island Storm Recovery and Resiliency, Fire Island, New York Conducting ongoing research focused on the collection and analysis of barrier island shoreline, shoreface, beach, and breach topography and bathymetry to determine the resiliency and evolution of barrier islands following tropical and extratropical storms. Utilizing bathymetry, GPS shoreline surveys, airborne imagery, and satellite-derived shorelines, developed metrics to describe breach evolution that demonstrate the importance of geology in breach migration and spit development in channel stability. The metrics were used to develop a hybrid Delft 3D-Xbeach geomorphic numerical model of breach evolution to identify processes controlling breach development and their influence on surrounding shoreline erosion and bay water levels. Satellite-derived shorelines were used to show the temporal and spatial extent of downdrift shoreline erosion following breach formation.

Sediment Transport Modeling

Temporal and Spatial Benthic Boundary Layer Evolution, South Carolina and Georgia Developed spatial and temporal models to predict bedform evolution, associated turbulence, sediment resuspension, and sediment flux. Analyzed existing published bedform geometries and bedforms from field experiments to develop an equilibrium ripple prediction model that improves predictions compared to existing models. Using seabed sector scanning sonar, developed metrics to quantify ripple shape as a function of variations in ripple length and orientation. Using time series of ripple geometries, further developed a time-dependent model that predicts instantaneous non-equilibrium ripple geometry and orientation under waves and currents.
Low-Density, Centimeter-Scale Sediment Motion, Northern Gulf of Mexico This work focused on improving sediment transport formulations for centimeter-scale low-density agglomerates. This research arose out of a necessity to understand the transport and fate of sand and oil agglomerates (SOAs) that formed along the northern Gulf of Mexico following the Deepwater Horizon accident and oil spill. Because SOAs have a lower density than quartz, a variety of shapes, and large size compared to surrounding sediment, existing sediment transport formulations do not adequately predict their mobility. Conducted research that led to the development of a semi-empirical formulation that predicts incipient motion threshold for SOAs of various sizes and shapes. This was accomplished through laboratory experiments using artificial SOAs with embedded inertial measurement units, 3D-printed SOAs, and computer vision tracking. The results of this work can be applied to existing sediment transport prediction for mixed-grain coral reefs, and to the transport of marine debris, munitions, and other insoluble contaminants.
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