Collaborative Research: Sediment Transport in Oscillating Turbulent Boundary Layers

University Of Maryland, College Park, College Park MD

Investigators

Abstract

0351667/0351443 A closely integrated numerical and experimental investigation of sediment transport mechanisms within turbulent oscillatory boundary layer flows will be conducted. The study will complement and extend the existing knowledge base through a focus on understanding the micromechanics of the transport process. The idea is to apply to the problem at hand techniques that have been developed during the last decade in the engineering community to study turbulent particle laden flows. On the numerical side, this will be done through the novel use of a combined Eulerian/Lagrangian Direct Numerical Simulation and Large Eddy Simulation of the fluid/particle motion using an immersed boundary technique and a two-fluid collisional wall model for the mobile sediment bed. The numerical modeling for the fluid phase will be done in conjunction with a Lagrangian based approach for the particulate phase to study the behavior, at the individual particle level, of the sediment entrainment mechanisms as well as the modification induced by the particles on the turbulence of the fluid phase. For the experiments, recent innovations in two-phase Particle Image Velocimetry techniques, pioneered in our laboratory, will be applied to provide detailed, instantaneous, spatially resolved measurements of both the fluid and the sediment phase within an oscillatory boundary layer water channel. The challenge is to adapt these techniques to the scales and parameter range encountered in the ocean. Broader Impacts The motion of sediments over the continental shelf is an important topic in coastal studies. Examples of applications include transport of particulate organic matter and man-made contaminants; prediction of the optical properties of the water column; evaluation of burial rates of archaeological artifacts; prediction of coastal flooding and erosion; evaluation of habitat of commercial fisheries; and the design of intakes and outfalls of sewage treatment plant and cooling systems. The development of a state-of-the-art experimental facility with a wide range of potential applications will open research possibilities in other areas, and foster further interdisciplinary collaborations. The development of a numerical tool incorporating the most advanced numerical techniques for the solution of two-phase wall-bounded turbulent flows will allow new insight of the process. The graduate students and a post-doc trained in this project will be exposed to advanced numerical and experimental techniques, within an exciting interdisciplinary environment. Finally, The output from model and experiments will be included in the teaching portfolio of the investigators.