Abstract
We have evaluated trajectory and velocity of tornado-borne objects using a numerical code, TONBOS, where wind of tornado is modeled with Fujita's tornado model, DBT-77, in addition to the conventional Rankine vortex model. Liftoff of an object placed on the ground can be considered by modeling lift force due to asymmetric flow pattern incurred by ground effect, while objects in air are assumed to randomly rotate and the translational motion is described by 3-Degrees-of-Freedom dynamic equations with drag and gravity forces. In this study, it is shown that the results of tornado-borne missile speed computed by TONBOS are comparable well with those of the previous studies, and that the degree of damage for a car computed by TONBOS is consistent with the damage descriptions of the Fujita scale categories.
