Turbulence question: How do view "the homogenous and isotropic turbulence"?
Abstract
In the statistical theory of turbulence, the clear-air turbulence in the atmosphere, the wind tunnel flow state in the core zone of the work area behind the grids, can be seen as a homogeneous and isotropic turbulence. Kolmogorov's study pointed out that the inertial set-range of spectrum function corresponds to homogeneous and isotropic turbulence; therefore, the scaling law is universal. From this, Kolmogorov deduced famous (-5/3) power law of turbulent energy cascade. But in the case observed intermittent and coherent structure in the experiments, it is needed to conduct comparative study between the energy cascade models and its corresponding scaling laws, the focus is to explore and study the physical mechanism of their statistical methods. Because there is a nonlinear term in N-S equation, especially the closure issues, which make the results of theoretical studies and numerical experiments have diversity and complexity, on this problem, there is no effective mathematical approach at present. In this paper, atmospheric turbulence as the central subject under discussion, several major issues related to this are discussed, namely: what is the problem of turbulence, turbulence theory and boundary layer theory, the nature of the turbulence problem, atmospheric turbulence, and the definition of the turbulence problem. We, especially, discuss the three different kinds of scaling laws, and look to prospects of turbulence research.
