Quantitative and Theoretical Analyses of an Experimental Helical Vortex

Abstract

This paper extends the earlier preliminary results of a laboratory simulation of a mesocyclonic circulation with an embedded tornadic vortex, produced by a vertically veering but nonrotating inflow with high helicity. Higher quality velocity measurements are performed which allow more detailed quantitative analyses, and are interpreted with the aid of a secondary flow model. The vortex is produced by vertical eddy transport of angular momentum generated by a helical secondary flow. The positive angular momentum on the right side of the inflow remains at low levels until it is stretched in the vortex core, while the negative angular momentum on the left side is lifted and carried out of the circulation.