Steering Committee For Wind Engineering Symposium

This paper reports a various set of the numerical simulation of tornado-like vortices considering the interaction with surface roughness. We tested the case of surface with forest. The result of steady- and unsteady- tornado-like vortices showed a significant difference from that of the case with relatively smooth surface (S_S). In the case of steady tornado, vortex breakdown occurred with strong convergence near the surface of SS was no more maintainable, instead, the radius of core become larger and updraft weaker. Turbulent region is widely spread in the margin of corner-flow. In the case of moving tornado, when tornado touched down the forest surface, a pressure drop was mitigated and new tornado core was born in the proximity of original core. It seems to take a hundred meter for the recovery of pressure drop after leaving the forest patch.