Research Progress

From the Clasic Theory of Turbulence to the Nonequilibrium Thermodynamic Theory of Atmospheric Turbulence

Updatetime:2012-04-09From:

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The turbulence is one of the ubiquitous natural phenomena in everyday experience, and a puzzle that is not yet fully resolved in classical physics. All the more so, it is a basic characteristic of the atmospheric motion. This paper reviews by the numbers the develop history of classic theory of atmospheric turbulence, further more introduces detailedly the nonequilibrium thermodynamic theory of atmospheric turbulence. In the nonequilibrium thermodynamic theory of atmospheric turbulence, the entropy equilibrium equation of atmospheric system with dynamic processes is introduced, and then Fourier′s and Flick′s laws, Newton′s Law deducted by, and both the Dufour and the Soret effects, the cross coupling effect between the dynamic and turbulent transport processes in the atmosphere, and the turbulent intensity theorem are uniformly proved by atmospheric nonequilibrium thermodynamics. These laws and theorem are partially validated by using observed data, further to determine their phenomenological coefficients. The turbulent intensity theorem reveals that the macroscopic cause of the development of fluid turbulence is a result of the shearing effects of velocity together with temperature and proves that both Reynolds turbulence and Rayleigh-Bé nard turbulence coexist in the atmosphere. The discovery of the coupling effect phenomenon between the thermodynamic and dynamic processes breaks through the viewpoint of the theories of traditional turbulent transport, Fourier′s and Flick′s laws, and Newton′s Law, i.e., the transport flux of one kind of macroscopic quantity is equivalent to the gradient turbulent transport flux of this macroscopic quantity. Moreover, the coupling principle between the thermodynamic and dynamic processes deems that the transport flux of one kind of macroscopic quantity should include the velocity coupling transport in addition to the gradient turbulent transport flux of this macroscopic quantity. Consequently, the vertical transport flux of energy and matter should count in the cross coupling effect of the vertical velocity, i.e., convergence and divergence motion, in addition to the turbulent transport flux caused by their vertical gradient. The earth′s surface is characterized by spatial heterogeneity over a wide range of scales.The heterogeneity of underlying surface brings on the advection to lead the convergence and divergence motion. It may be an important cause of the imbalance of energy budget of the ground surface. The cross coupling principle of the vertical velocity and vertical turbulent transport may offer a possible clue to the theory of atmospheric boundary layer with heterogeneous underlying surface and to overcome the difficulties encountered in the imbalance problem of ground energy budget and in the parameterization of boundary layer with the heterogeneous underlying surface.

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