Mechanics of Turbulence of Multicomponent Gases (Astrophysics and Space Science Library Book 269)

Space exploration and advanced astronomy have dramatically expanded our knowledge of outer space and made it possible to study the indepth mechanisms underlying various natural phenomena caused by complex interaction of physical-chemical and dynamical processes in the universe. Huge breakthroughs in astrophysics and the planetary s- ences have led to increasingly complicated models of such media as giant molecular clouds giving birth to stars, protoplanetary accretion disks associated with the solar system’s formation, planetary atmospheres and circumplanetary space. The creation of these models was promoted by the development of basic approaches in modern - chanics and physics paralleled by the great advancement in the computer sciences. As a result, numerous multidimensional non-stationary problems involving the analysis of evolutionary processes can be investigated using wide-range numerical experiments. Turbulence belongs to the most widespread and, at the same time, the most complicated natural phenomena, related to the origin and development of organized structures (- dies of different scale) at a definite flow regime of fluids in essentially non-linear - drodynamic systems. This is also one of the most complex and intriguing sections of the mechanics of fluids. The direct numerical modeling of turbulent flows encounters large mathematical difficulties, while the development of a general turbulence theory is hardly possible because of the complexity of interacting coherent structures. Three-dimensional non-steady motions arise in such a system under loss of la- nar flow stability defined by the critical value of the Reynolds number.

Turbulence in multicomponent reacting gas mixtures is an important mechanism underlying numerous natural phenomena closely related to the study of our space environment. This book develops a new mathematical approach for modelling multicomponent gas turbulence that adequately describes the combined processes of dynamics and heat and mass transfer when chemical kinetics and turbulent mixing are equally important. The developed models include the evolutionary transfer equations for the single-point second correlation moments of turbulent fluctuations of thermohydrodynamical parameters. The phenomenological approach to the closure problem in hydrodynamic equations of mean motion at the level of the first order moments is based on the thermodynamics of irreversible processes and enables defining relationships in a more general form as compared to those conventionally deduced using the mixing path concept. Based on the developed approach, turbulent exchange factors for a planetary upper atmosphere are evaluated, and a turbulent model of a protoplanetary accretion gas-dust disk involving heat and mass transfer and coagulation is also considered.
As compared to previously published books on the problem of turbulence, this book deals, for the first time, with the complicated models of reacting gas mixtures. It is intended for graduate and postgraduate students in the fields of fluid gas dynamics, astrophysics, space physics, planetary sciences, and aeronomy, and especially for those dealing with computer modelling of the processes in such natural media. The book may also be of interest to specialists in the relevant fields of ecology, engineering, and material processing.

Turbulence in Natural Media....Pages 6-64 Regular Motion of Gaseous Mixtures Involving Physicochemical Interactions of the Components....Pages 65-111 Turbulent Motion of Multicomponent Mixtures with Variable Thermophysical Properties....Pages 112-165 Evolutionary Transfer Models for the Second Correlation Moments....Pages 166-205 The Stefan-Maxwell Relations and the Heat Flux for Turbulent Multicomponent Continuum Media....Pages 206-229 Diffusion Processes in the Thermosphere....Pages 231-254 Turbulent Transfer Coefficients in Planetary Upper Atmospheres: A Semi-Empirical Determination....Pages 255-269 Statistical Parameters of Turbulence: Modeling from Fluctuations of the Refractive Index....Pages 270-307 The Processes of Heat and Mass Transfer and Coagulation in Protoplanetary Gas-Dust Nebula....Pages 308-350 Turbulent motion is a chaotic unsteady motion superimposed on basic motions of a liquid (gaseous) medium, which are referred to as statistically averaged motions.