A numerical investigation of building damage during the 6 May 2012 Tsukuba tornado using hybrid meteorological model/engineering LES method

Abstract

To validate applicability of the novel hybrid meteorological model/engineering LES method to damage estimation of actual tornado events, simulation is performed focusing on the severely damaged area of the strong tornado on May 6, 2012 in the city of Tsukuba with the realistic tornado structure reproduced in the meteorological model, the actual building distribution, and the topography. The flows over the disaster-affected low-rise residential area show an evident converging character at a height close to the rooftops. Intense strong wind bands are formed by the influence of the buildings. The simulated maximum wind gust is compared with the distribution of actual building damage. It reveals that the hybrid method can reasonably estimate distribution of the building damage over the target area in the tornado event. The track nevertheless exhibits building-scale perturbation that may be attributed to chaotic randomness of the tornado behavior on the complex rough surface. Using the simulated aerodynamic force, simplified case studies on the occurrence and process of damage to two individual buildings is also presented.