The transformations which are responsible for the decreased temperatures inside tornadoes have been scientifically analyzed. For the first time, a research paper makes an analytical description of the phenomenon.
The study, published online, Jan. 11, in the Journal of Aircraft of the American Institute of Aeronautics and Astronautics, represents the analysis on a very violent tornado which took place in 1955, in Scottsbluff, Nebraska.
The Mechanics Of Tornado Temperatures, Finally Explained
During the tornado, three members of a local radio station were live from the scene and took shelter in the basement of a stone building. Inside, they noticed bizarre climatic changes, among which the temperature dropping from a mid-summer average, progressively, until the reporters were feeling plain cold. They also reported that it's increasingly difficult to breathe as the tornado passed through the area where they were hiding.
Since that storm, 61 years have passed. The exact cause of the phenomena accompanying the tornado, however, remained unexplained until this new research, where a mathematical model of a turbulent compressible vortex was formulated.
In an attempt to solve this mystery, Georgios Vatistas, the scientist who led the research, expanded his previous theoretical research on vortices. The new analysis includes the effects described by the radio broadcasters, i.e. density variation and turbulence
"Using this new advanced approach, we were able to identify the cause of the temperature drop inside vortices for the first time ever," noted Vatistas.
The research team spotted the cause responsible for the temperature drop inside vortices, which is a first-time formal discovery.
"[...] the present investigation identifies the cause of the Ranque-Hilsch-like thermal effect observed in unconfined compressible vortices. In comparison to laminar vortices, the center of a turbulent gaseous vortex is found to be cooler, thinner, and under lower-pressure conditions," noted the research paper.
The research team discovered that the temperature dropped from 27°C (80.6°F) to 12°C (53.6°F). According to the paper, the air density was 20 percent lower compared to high altitudes.
The researchers observed that, far from the axis of the rotation, the gas heated up at first, reaching a static temperature maximum and then went down to a subambient minimum at the vortex center. This theory is in complete opposition compared to previous scientific papers, as part of which the converging flow cooled down monotonically with decreasing radius.
The importance of this research, however, does not just address the phenomenon of tornadoes, as the data could also be employed in other connected fields where temperature mechanics are important, ranging from electronic compounds to heal seals.
Tornadoes, A Recurring Phenomenon
Tornadoes are a recurring phenomenon in the United States, where the average number of tornadoes per year is 1,224. According to data by U.S. Tornadoes, some states are in more danger than others, as data from 1991 to 2015 suggests.
"The top 10 states for tornadoes as of the most recent average are as follows, in order from high to low: Texas, Kansas, Oklahoma, Florida, Nebraska, Illinois, Colorado, Iowa, Alabama, Missouri, and Mississippi," noted the website.
