CAREER: On The Hydrodynamics of River Ice

North Dakota State University Fargo, Fargo ND

Investigators

Abstract

River ice drives many disasters, such as flooding, scour, ice jams, and bank erosion. Understanding this flow will lead to new mitigation measures and prevention methods for disasters in streams and rivers. However, this problem is very complex because it requires obtaining turbulent flow data at a large disparity in spatial scales, from the level of macro-roughness on the channel bed to the entire channel planform (kilometers). The proposed project will use field measurement, theoretical analysis, and numerical simulation as a holistic approach to understanding the key factors that govern the river ice processes. This proposal's educational plan focuses on the three-prong collaborations with the Red River Keepers, the ND EPSCoR Office, and the USGS North Dakota Water Science Center to provide accessible scientific activities for local K-12 students and teachers. These educational activities are aimed at kindling the interests of K-12 students in winter hydraulics. Furthermore, a series of seminars and workshops will be organized to inform the general public and the authorities about the importance of icy flows. This proposal aims to integrate research and educational activities, the Ice-Flows project, based on the idea that ice coverage dictates the turbulent flow characteristics of rivers in winter. One unique contribution of the proposed research is developing a theoretical approach to investigate the impacts of ice coverage on bed shear stress in meandering rivers. While the distribution of bed shear stress has been studied before in laboratory settings, it has rarely been studied in alluvial channels. Another core novelty of the proposed work is a model for cross-stream momentum transfer in ice-covered rivers. Using field measurement and numerical simulation, the proposed model will reveal the link between the cross-stream momentum transfer and the three-dimensional structure under ice coverage. The PI's development of a state-of-the-art numerical framework for Large Eddy Simulation is the essential tool to analyze icy flows at roughness scales for alluvial channels. The proposed LES model will be used as a tool to investigate the hydrodynamic impacts of ice cover at a large disparity of spatial and temporal scales. Therefore, the proposed project has the potential to transform the current engineering practices, which have been primarily based on empirical relationships. This project is jointly funded by Fluid Dynamics program and the Established Program to Stimulate Competitive Research (EPSCoR) program. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.