EXPLORATORY MODEL STUDY OF TORNADO-LIKE VORTEX DYNAMICS

Abstract

In a laboratory model of the tornado-like vortex near the ground, the circulation is produced by a rotating cylindrical screen and the updraft is produced by an exhaust fan at the opening of the top hood. By means of kerosene smoke, the vortex core and a reverse flow zone were observed. The profiles of velocity and pressure were measured at three different circulation strengths. The maximum inward radial velocity in the boundary layer is approximately proportional to the circulation strength. The vertical velocity distribution generally has a Gaussian profile except that it is slightly downward in the annular reverse flow region.