Collaborative Research: CROSSTEX - Wave Breaking and Boundary Layer Processes and the Resulting Sediment Suspension in the Surf zone

Oregon State University, Corvallis OR

Investigators

Abstract

Intellectual Merit: The CROs-Shore Sediment Transport EXperiment (CROSSTEX) project has been developed to fill in the gap between complex field conditions and small-scale laboratory experiments. This project will focus on the physical mechanisms of nearshore hydrodynamics and sediment transport in the surf zone and in particular the relative importance of wave breaking turbulence and bottom boundary layer turbulence on nearshore sediment suspension processes. The Large Wave Flume at Oregon State University serves as the focal point for this project, and the project combines the unique talents of researchers who have traditionally worked in the three areas of laboratory experiments, field work, and numerical modeling and provides an opportunity to advance the state of the science in nearshore modeling of sediment transport. One of the expected outcome is a better understanding at space- and time-scales relevant to process-based models and a set of benchmark data sets for validation of numerical models. The latest advances in instrumentation to measure turbulent stresses in the water column and boundary layer, advances in web-based data archival and retrieval for data sharing and collaboration, and the latest implementation of numerical codes and computer resources will be combined. For example, instrumentation and experimental techniques will be combined into three sub-arrays for observing three phase flow (instantaneous velocity, sediment suspension, and void fraction) with each overlapping and focusing on a particular part of the water column: the surface layer, below trough level, and the bottom boundary layer including bottom roughness. The numerical modeling will be divided into three sub-areas to resolve issues of space/time scales and varying in complexity (e.g., one- or two-phase flow; complexity of turbulence closure schemes). Broader Impacts: The Wave Research Laboratory (WRL) is an NSF REU (Research Experience for Undergraduates) site for nearshore science and hazard mitigation (http://wave.oregonstate.edu/). Dr. Cox is the lead PI for the site and 3 co-PIs on the two other CROSSTEX proposals serve as faculty mentors. Each summer, these mentors and their graduate students work with 10 talented undergraduate on active research projects with an overall goal of encouraging these students to consider graduate school. Half of the REU students are from under-represented groups, and half come from outside of OSU. For Years 1 and 2 of this project, at least 5 of the REU students will be involved in the CROSSTEX project. The WRL is actively engaged in K-12 educational programs and outreach as part of its designation as an NSF-NEES site. The WRL is currently working with education and outreach people and programs to develop a comprehensive K-12 education and outreach program which will be used to highlight the CROSSTEX project. During this four-year project, several graduate students at OSU, Ohio State, and U. Florida will receive training in sophisticated experimental and numerical techniques.