|СТРАНИЦА БОРИСА ГОРДЕЙЧИКА|
|СПИСОК НАУЧНЫХ ТРУДОВ||BORIS GORDEICHIK HOMEPAGE|
|LIST OF SCIENTIFIC WORKS|
Zababakhin Scientific Talks - 95
COMPUTATIONAL MODELING OF TURBULENCE CHARACTERISTICS IN THE BURST CLOUD
B.N. Gordeichik, M.D. Scherbin, V.N. Zabavin
Central Institute of Physics and Technology, Defence Ministry of Russian Federation, Sergiev Posad-7
Process of cloud generation and evolution with influence of turbulence on it is considered.
In preceding authors' works the prevailing influence of vorticity generation and transport on the principal features of disturbed atmosphere region is proved. The consequence of it is formation of buoyant vorticity ring from a hot gas ball. The turbulence has no decisive influence on the flow, because of radial turbulent streams (heat, impulse) are suppressed in vortex ring core as a consequence of centrifugal acceleration and temperature gradient. That is why in preceding computational models the nonviscous fluid approach is used. But information on turbulence characteristics has a practical interest, and the present report is the development of existing models.
The gas motion is described by Reynolds equations. The present computational method is suggested for its solution. The processes of vortex generation and transfer (convection) and turbulent diffusion are processed apart. Convection is modeled by means of scheme with a small numeric viscosity, and the diffusion ( with the aid of usual implicit scheme. The turbulence model is restricted by two equations: turbulence energy equation and temperature pulsation equation. Turbulent scale is required to lock this turbulent model. It was chosen from corresponding experimental and computational works. Besides the turbulent streams suppression in radial direction of vortex ring core were taken into account by corresponding decrease of turbulent scale.
The spectrum data is determined by the universal dependence, which was deduced by means of asymptotic coalescence of low wave numbers, inertial and dissipative intervals for homogeneous isotropic turbulence of scalar quantity.
Calculation results of burst on the heights of 10...40 km are in satisfactory agreement with experimental data on geometrical characteristics of a buoyant vortex ring and its rise; the mean and spectral characteristics of turbulence are obtained for all stages of burst cloud development.