Could the Twin Towers collapse teach the interaction of dilute pyroclastic density currents with buildings?

Abstract

Particle-laden turbulent flows, called dilute pyroclastic density currents, can be generated during explosive volcanic eruptions. They are the most hazardous events of interaction with buildings and human environments in volcanic areas. A qualitative comparison with the dusty turbulent shear currents generated after the Twin Towers collapse on September 11, 2001 shows that turbulent, multiphase flow-building interaction causes flow separation and recirculation around the buildings. This simple idea could be applied to dilute pyroclastic density currents, and improved in future by adhoc numerical simulations of flow-building interaction.