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

这项职业计划的主要研究目标是描述泥沙颗粒随机运动的特征，并科学地量化常规和极端水流中水流和含沙量以及输移率预测的变化和不确定性。这项拟议的工作集中于检验一个创新想法的适用性，该创新想法受到1997年诺贝尔奖期权定价理论工作的启发，以更好地描述极端事件期间粒子的随机粒子跳跃扩散过程。我们假设天然河流中泥沙颗粒的位移服从一个由平均漂移项、水流湍流驱动Wiener过程和响应极端水流事件的跳跃泊松过程组成的随机跳跃扩散过程。提出了一种基于物理的三维随机偏微分方程组(SPDE)悬浮泥沙输运模型，该模型由基于随机跳跃扩散的颗粒跟踪模型、基于大涡模拟的水动力模型和质量输运方程组成。建议的模型将根据实验室测量和现有数据进行验证。改进的罗森布鲁斯方法将被用来量化常规和极端事件流中的沉积风险。本研究项目旨在解决以下关键问题：(1)如何在泥沙输移模拟中有效地量化贡献水沙变量的时空变异性和模型参数的不确定性？(2)水沙特性的统计特征如何有助于提供更科学的风险评估和泥沙淤积和水质控制所需的安全系数？(3)大多数泥沙沉积过程发生在洪水等极端水流事件期间。我们如何将极端事件发生的概率纳入泥沙输运模型？如何从极端水流事件中区分正常水流期间的沉积过程或水污染的不确定性来源？这份职业建议书中的教育目标有三个：激励学生？提高学生的学习兴趣，提高他们的量化技能，让学生参与研究，并指导学生，特别是妇女和少数族裔学生的职业发展。PI将通过创造性的教学改革来提高教育质量，并作为教师顾问、职业顾问和榜样进行指导。主要的教育活动包括运用认知发现教学和学习。范式和简单解决复杂？在量化课程中的教学理念，创造性和创新性的技术应用，将研究纳入教学，长期的招聘和留住女性和少数族裔学生的努力和外联活动，以及学生参与研究。

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.