An Experiment on the Rotation Source of the Small Scale Atmospheric Vortices

Abstract

The flow characteristics of the small scale atmospheric vortices are investigated based on a laboratory experiment for various types of ambient circulation. The following results are obtained when the ambient circulation is supplied in the upper layers: 1) The radial distributions of velocity are found to have two maxima, which may correspond to the cores of the tornado and the mesocyclone respectively, 2) the vortex breakdown occurs at small inflow angles when Reynolds number is large, and the swirl angles near the core are larger than those when the ambient circulation is supplied throughout the whole convergence layer, and 3) lower layers have steeper radial gradient of the horizontal velocity compared to the upper layers right outside of the core.