CAREER: STOCHASTIC MODELING AND UNCERTAINTY ANALYSIS OF SEDIMENT TRANSPORT IN REGULAR AND EXTREME SURFACE FLOW ENVIRONMENTS

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The primary research goals of this CAREER proposal are to characterize the stochastic movement of sediment particles and to scientifically quantify the variation and uncertainty of flow and sediment concentration and transport rate predictions in both regular and extreme flows. The proposed work focuses on examining the applicability of an innovative idea inspired by the 1997 Nobel Prize work on Option Pricing Theory to better describe the stochastic particle jump diffusion process of particles during extreme events. We hypothesize that the displacement of a sediment particle in natural rivers follows a stochastic jump diffusion process consisting of a mean drift term, a driving Wiener process due to flow turbulence, and a jump Poisson process in response to extreme flow events. A physically based 3-D stochastic partial differential equation (SPDE) based model for suspended sediment transport will be developed, which is composed of an innovative stochastic jump diffusion based particle tracking model, a hydrodynamic model using large eddy simulations (LES), and a mass transport equation. The proposed model will be validated against laboratory measurements and existing data. The modified Rosenblueth method will be used to quantify the risk of sedimentation in both regular and extreme event flows. This research project aims to address the following critical issues: (1) How can the spatial and temporal variability of the contributing flow and sediment variables and the uncertainty of the model parameters be effectively quantified in sediment transport modeling? (2) How can statistical characteristics of flow and sediment properties assist in providing a more scientifically based risk assessment and safety factors needed for sedimentation and water quality control? (3) Most of the sedimentation processes occur during the extreme flow events such as floods. How can we incorporate the probability of extreme event occurrences into sediment transport modeling? How can one distinguish the uncertainty sources of sedimentation processes or water pollution during regular flow periods from the extreme flow events?The education goals in this CAREER proposal are three-fold: to stimulate students? learning interest and improve their quantitative skills, to engage students in research and to guide students, particularly women and minority students, in their career development. The PI will improve the quality of education through creative pedagogy changes to teaching and mentorship as a faculty advisor, career consultant and role model. Major educational activities include the use of the ?cognitive discovery teaching and learning? paradigm and the ?simplicity solves complexity? teaching philosophy in quantitative courses, creative and innovative implementation of technology, incorporation of research into teaching, longer-standing recruitment and retention efforts and outreach activities of female and minority students, and student involvement in research.