Jiamin Dang, a doctoral candidate in civil engineering, will defend their dissertation titled “Advancing Tornado Simulation using Coupled CM1 and High-Resolution LES and Enhancing Tornado Resilience.” Their advisor, Dr. Grace Yan, is professor in the civil, architectural and environmental engineering department. The dissertation abstract is provided below.

In recent years, tornado induced property damage, injuries and fatalities have been increase. The harsh environment around tornadoes and unpredictable tornado paths makes it impossible to characterize the tornado characteristics and dynamics using field measurement. The interactions between a tornado and ground features may change the tornado path and intensity, complicating the characterization of tornadic wind field. Therefore, it is imperative to develop an advanced numerical simulation approach that can capture realistic tornado wind characteristics in the wind field and realistic wind effects on civil structures. To achieve this, this study proposes a coupled simulation approach by coupling a storm-scale meteorological model, Cloud Model 1 (CM1) and a tornado-scale High resolution Large-Eddy Simulation (HLES) model to advance the tornadic wind simulation. First, the methodology of coupling CM1 and HLES is introduced, and the performance of the coupled model is evaluated by comparing with the original CM1-simualted tornado and previous tornado simulation approaches with identical inputs along boundaries. Second, the coupled model is applied to reproduce community-level damage induced by the 2021 Midwest Tornado Outbreak, leading to a calibrated model to assess the potential retrofit schemes to guide the post-disaster reconstruction. Third, the influence of terrains on tornado behaviors is investigated by introducing idealized hill and escarpment terrains with two slopes, as well as a real-world complex terrain relief, on the bottom boundary in the LES domain. Fourth, the influence of land covers on tornado behaviors is also investigated by introducing five types of land covers on the bottom boundary in the LES domain. Finally, the research work conducted is summarized and the envisioned future work is provided