Spatial distribution of horizontal velocity components of tornado-like vortices measured by PIV and comparison with vortex models

Abstract

Tornado is one of the factors of strong wind damage of buildings in Japan. In order to reduce the damage of tornado, it is necessary to investigate what property the tornado flow has. This study aims to clarify the wind velocity distribution of tornado vortex by using the tornado-like flow simulator, obtaining the flow velocity of the flow field by PIV. As a result, there was a maximum value of the wind speed in the vicinity of the ground. In that region the variation in the wind speed was high. According to the radial distance from the center , the tangential wind speeds increased to the maximum value of the wind speed and decreased from there for each height. A bimodal distribution was observed at a part of the height. Furthermore, radial distributions of tangential wind speeds and vorticities were similar to those of Burgers vortex.