乱流の統計理論

概要

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The nonlinearity in the Navier-Stokes equation leads to the infinite number of hierarchy of coupled moment equations. It has been a long challenging problem in the theory of turbulence how to close it by reasonable analysis.Here, a promising perturbation thoery is discussed, which is based upon quite different idea from the standard perturbation theory. The present theory is similar in some respects to Kraichnans direct-interaction approximation (DIA). But they are essentially different in idea, procedure as well as applicability. After a brief review of previous works of closure problem, we introduce the sparse direct-interaction perturbation (SDIP) method and formulate it for a quadratic nonlinear dynamical system. The basic assumptions and procedures of this perturbation theory are explained in detail. The results are compared with the direct numerical simulation of the system.
プラズマ・核融合学会の論文
2002-08-25