The natural phenomenon of a tornado, known for its destructive power, is an object of study of many scientists. The available part of the data of field observations of this natural phenomenon is systematized and collected in the so-called Fujita scale. In particular, it indicates the width of the fracture band for tornadoes of different intensity, and only the values of the maximum wind speed are given from the gas dynamic parameters. Bautin S.P. proposed and justified the scheme of occurrence and functioning of natural ascending swirling flows of the tornado and tropical cyclones. Based on both this scheme and the data of the Fujita scale, the external radii of air inflow in the near-bottom parts of tornadoes of various intensities are established and the gas dynamic parameters of these flows are calculated. It turned out that in the case of the lowest intensity from the Fujita scale, the kinetic energy of the rotational motion of the air is half of the entire kinetic energy of the flow in the bottom part. As tornado intensity increases, the kinetic energy of rotational motion becomes the more prominent part of the total kinetic energy of the flow. In this paper, given the Fujita value of the width of the destruction zone for all tornadoes along with the two external radii of air inflow into the bottom part of the tornado are established as rin1 and rin2. The first of these radii, namely rin1 , denotes the radius at which the kinetic energy of the rotational motion of the constructed stream is half of all the kinetic energy of this stream. The second one denoted as rin2, is the radius at which the kinetic energy of the entire stream becomes equal to the kinetic energy of the weakest destructive tornado. Knowing the values of these radii allows reliable predicting the origin of the tornado.

В настоящей работе при заданном в таблице Фудзиты значении ширины полосы разрушений для всех торнадо установлены два внешних радиуса притока воздуха в придонную часть торнадо: in1 и rin2. Первый из этих радиусов in1 такой, что кинетическая энергия вращательного движения построенного потока составляет половину всей его кинетической энергии. При втором радиусе rin2 кинетическая энергия всего потока становится равной кинетической энергии самого слабого торнадо, при котором имеют место разрушения. Знание значений этих радиусов позволит более надежно прогнозировать возникновение торнадо.

№5(23) (2018)