Using High-Resolution Simulations of Tornadoes Interacting with Urban Structures to Improve Resilience

Understanding near-surface wind speeds in tornadoes is critical to increasing resilience to tornado damage and mitigating societal risk (e.g., through building code improvements). Near-surface winds in tornadoes can change non-trivially in response to surface landcover (e.g., buildings) and topography owing to the sensitivity of tornado wind speeds to near-surface, angular momentum fluxes modified by surface friction. To better understand how wind speeds vary in urban areas, physically based, numerical simulations can be employed to model the tornado’s dynamical response to buildings encountered along its path.

The goal of this study is to examine the effects of residential structures on the tornado wind speed. High-resolution numerical simulations are conducted using Cloud Model 1 (CM1) to generate a tornado vortex, and an immersed boundary method is used to simulate different types of buildings (homes, commercial buildings). Realistic neighborhood simulations are conducted to assess how the tornado’s winds are modified within a typical residential area compared to residential buildings in isolation. Notable effects include small-scale wakes that emanate from houses and provide sheltering effects to downstream structures in the neighborhood. Wind speeds affecting buildings also vary depending on the residential layout, such as the width of the street and its orientation to the tornado’s track. Future plans to incorporate a realistic damage parameterization model into CM1 building simulations will be discussed, as well as ongoing efforts to validate these simulations through engineering damage assessments.