Ground roughness effects on internal pressure characteristics for buildings exposed to tornado-like flow

Tornadoes pose serious threat to buildings and structures. Studies related to tornado-structure interaction are often restricted to post-damage investigations. Detailed tornado-structure interaction studies are required to understand the basic flow mechanisms that inflict damage. Terrain roughness is often a criterion that determines the strength and characteristics of tornado and consequently its effect on structures. In the present investigation, the effect of ground roughness on the internal pressures developed inside a building model exposed to a stationary vortex is analyzed using the Ward-type tornado simulator at Tokyo Polytechnic University. The effects of ground roughness on net local roof wind forces are also investigated. Results show that the internal pressures decrease in magnitude with introduction of roughness, whereas the resulting net local roof forces increase in magnitude with introduction of roughness.