Abstract:Tornado vortex simulator (TVS) in Tongji University was constructed to generate translating tornado like vortices for the physical simulation of tornado like vortex and quantifying tornado induced aerodynamic loads on structures. A controlled fan, an annular duct and turning vanes suspended from the overhead crane composed the main parts generating tornado like vortex, which could also be translated as a whole along a ground plane at the maximum speed of 0.4 m·s-1. The tornado like flows with swirl ratios ranging from 0.11 to 0.54 achieved by changing vane angle (θV=20°~60°) were simulated by the simulator and measured with TFI Cobra Probes. The flow structures of the vortices were validated by comparing with the mobile Doppler radar observations of three major tornados happened in Spencer, South Dakota May 30, 1998 and Mulhall, Oklahoma May 3, 1999 and Manchester, South Dakota June 24, 2003 respectively. The structures of the tangential velocity and the surface pressure of the simulated tornado like flow were found to agree well with the measured data of the tornados, indicating that this simulator could generate stable tornado like vortex and be used to simulate tornado like flow physically.
