An investigation of the major characteristics of surface pressure fields beneath two types of tornado-like vortices and their causes

A series of experiments were performed in a tornado simulator to study tornado-like vortices, with a focus on the surface pressure fields beneath the vortices. In the experiments, the pressures on the floor beneath a single-celled vortex and a two-celled vortex were measured. The measurements were used to characterize the surface pressure fields, which revealed, among others, the spatially varying non-Gaussian distribution of the surface pressures, the existence of narrowband components in the pressure fluctuations, and the differences between the characteristics of the surface pressure fields beneath the two types of vortices. A further analysis of the time and spatial variations of the surface pressure fields enabled the identification of the phenomena that cause these major characteristics of the surface pressure fields and the specific differences in these phenomena that result in the differences in the characteristics of the surface pressure fields beneath the two types of vortices. The findings from the study of the surface pressure fields provided insights into the nature of the tornado-like vortices aloft.