报告题目:Backtracking using an adjoint subordination model: From source identification to aquifer vulnerability assessment
报告时间：2022年06月10日9:00-11:00（北京时间）
报告地点：线上腾讯会议（ID: 935-893-226）
报 告 人： Yong Zhang教授, 阿拉巴马大学, 美国
主 持 人： 孙洪广教授
主办单位：力学与材料学院水力学与流体力学研究所
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报告简介：
Backtracking and/or backward probabilities had been used by hydrologists for four decades in water-quality related applications. Reliable calculation of backward probabilities, however, has been challenged by non-Fickian pollutant transport dynamics and variability in the resolution of velocity at study sites. To address these two issues, this study built an adjoint model by deriving a backward-in-time vector fractional-derivative transport equation subordinated to regional flow, developed a fully Lagrangian solver, and applied the new approach to backtrack pollutant transport in a wide range of flow systems. The resultant adjoint subordination equation in a bounded domain characterizes direction-independent sub-diffusion via the time fractional derivative term with mixed, reversed vector super-diffusion along streamlines due to non-local mechanical dispersion, which can backtrack anomalous transport in multi-dimensional natural geomedia more efficiently than traditional vector fractional-derivative equations. Field applications demonstrate that the adjoint subordination model can recover pollutant release history in rivers or porous/fractured media, date groundwater age in regional-scale alluvial aquifers, delineate well-head protection zones, and identify spatial locations of pollutant sources for various flow systems.
报告人简介：
Dr. Yong Zhang is a professor in Department of Geological Sciences in University of Alabama, U.S. He has published 50 first-author papers in hydrology, physics, and math journals.