Experimental and Numerical Investigation of Grain Shape Effects on Littoral Sediment Dynamics and Transport of Munition Constituents
Abstract
This proposal describes a plan to advance coastal engineering research and education at the University of Puerto Rico-Mayaguez (UPRM) with particular focus on sediment transport processes within the littoral bottom boundary layer. A solid research program and a strong plan to enhance UPRMÕs research capabilities and promote a culture of research are integrated throughout the proposal, grounded on the overarching goals of improving predictions of irregularly shaped sediment dynamics in the littoral zone; while advancing the representation of women and minorities in the fields of coastal engineering and littoral geosciences. Littoral evolution, mine burial and unburial, and the transport of munition constituents seeping from unexploded ordinances are closely related to the dynamics of sediment transport occurring at the wave-bottom boundary layer of the littoral zone. For the case of non-cohesive sediment beds, predictive models of sediment dynamics have strongly rely on formulations developed for spherical grains, which closely resemble silica sands. However, in tropical littoral zones, non-cohesive sediments are usually composed of calcareous sand exhibiting coral, shells and other marine fragments with a variety of shapes and angular features. The irregular nature of these types of sediments increases intergranular friction thereby hindering sediment mobilization. While some efforts of river hydraulics have studied this phenomena for steady, unidirectional flow conditions, only a few have focused on wave-dominated environments, most of which have been numerical simulations with significant simplifications of particle geometry. Through detailed laboratory observations of the nearbed velocity field, bed geometry, and bedload transport under full-scale oscillating fluid motion, this project aims to accurately quantify the effects of grain shape and angularity on the initiation of motion, bedform development and evolution, and bedload transport under the presence of waves. The experimental program will be complemented by a numerical modeling effort using state-of-the-art Computational Fluid Dynamics - Discrete Element Methods (CFD-DEM) software that seeks to study more complex physics that cannot be simulated in the experimental facility. The knowledge gathered through this study has the potential to impact the way current deterministic models predict sediment transport in littoral bottom boundary layers of tropical zones with implications for littoral evolution, mine burial and unburial, and the transport of munition constituents seeping from unexploded ordinances. This research program will be integrated into an educational component that seeks to promote, establish, and maintain a culture of research at all levels. First, in order to stimulate research activity, productivity, and interactions, the Coastal Boundary Layers Research Group will be complemented by the addition of a postdoctoral researcher and a laboratory manager. In order to effectively reach a broader audience, interactive mini-wave flume modules on coastal evolution and sediment transport will be developed to attract the next generation of coastal engineers and scientists through early recruitment strategies. Additionally, the PI will use the enhanced research capabilities that this grant entails to aid students in the preparation and submission of the NDSEG fellowship and other national fellowships.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010267
Entities
People
- Sylvia Rodriguez-abudo
Organizations
- Army Contracting Command
- Office of the Secretary of Defense
- University of Puerto Rico at Mayaguez