Photo: Sergey Savostyanov / TASS
Scientists from the Institute of mechanics of Moscow state University is defined as random fluctuations of speed of rotation, or noise, affect the number of vortices in spherical Couette flow. It turned out that between the noise and the flow regime is a complex nonlinear relationship. This will allow you to build a more accurate model of natural currents, including circulation of Earth’s atmosphere. The results published in the journal Chaos. About it reported in a press release, which is at the disposal “of the Tape.ru”.
Spherical Couette flow is the flow of liquid in a spherical layer caused by the rotation of its borders. In the laboratory study it at the installation of the two transparent areas: the external, usually remains fixed and the inner rotates at a given speed. This model allows to describe turbulent processes: large-scale motion of the atmosphere, oceans and the Earth’s mantle caused by the rotation of the planet. The first step on the path to turbulence is the loss of stability of stationary flow, resulting in the flow of liquid or gas spontaneously arise vortices.
The mode of the Couette and the number of vortices is determined by the magnitude of the acceleration with which changes the rate of rotation of the inner sphere. In the new experiment, the researchers decided to test how the flow regime is influenced by random fluctuations in the speed of rotation (noise). Specifically, the experimenters increased the noise and determined the number of vortices in the liquid.
It turned out that between random interference and the regime of fluid flow actually exists nonlinear dependence. When the noises are made by scientists, was small, for there were three of the vortex, as in the absence of additional noise. When a large noise impact acceleration “forgotten”, and within formed with four vortex. In the case of noise of average amplitude, the number of vortices depends on the magnitude of the acceleration, and the noise value, and this dependence is nonlinear.
The results will help assess the impact of noise on the processes in natural objects: pulsars in the Earth’s atmosphere and other planets. For example, random fluctuations in the inflow of solar heat in the atmosphere, as suggested by some researchers, can change elements of atmospheric circulation: the cells of Hadley, Ferrel and polar. These cells represent a ring with a closed air circulation, and atmospheric circulation in them depends directly on the climate of the whole planet.”
Video, photo All from Russia.