- Characteristics of Numerically Generated Tornado-like Vortex
A numerical tornado simulator was developed and a tornado-like vortex was generated numerically by Large Eddy Simulation. The tornado simulator consists of a convection region and a convergence region. A series of unsteady flow fields of vortex were generated and examined the flow characteristics with varying the inflow conditions, the boundary conditions, and the configuration of calculating domain. Some of the typical vortices ; single core type without mean down flow region in the core, single core type with mean down flow region in the core, multiple core type and swirling core type were presented. The flow characteristics of the single core type with mean down flow region in the core were examined. The common future of these vortices was summarized as, 1. The differential pressure ? P from the surrounding mean pressure decreases to the value of 2?P/ρV2tmax=-1.5 at the position where the maximum tangential wind speed occurs, where is ρ the air density, Vtmax the maximum tangential wind speed. 2. The tangential wind speed decreases to the half of Vtmax at three times of the maximum tangential wind speed radius.
- 京都大学防災研究所年報. B = Disaster Prevention Research Institute Annuals. B
京都大学防災研究所年報. B = Disaster Prevention Research Institute Annuals. B 53 (B), 383-390, 2010-06-01