Accession Number : ADA017716

Title :   A Closed Stochastic Approximate Model for Time Dependent Turbulent Flows.

Descriptive Note : Interim rept.,

Corporate Author : VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIENCE AND MECHANICS

Personal Author(s) : Besieris,Ioannis M. ; Stasiak ,Wojciech B. ; Telionis,Demetri P.

Report Date : AUG 1975

Pagination or Media Count : 39

Abstract : Working along the lines of a procedure outlined by Keller, a technique is developed for deriving closed first- and second-order moment equations for a general class of stochastic nonlinear equations by performing a renormalization at the level of the second moment. The work of Weinstock, as reformulated recently by Balescu and Misguich, is extended in order to obtain two equivalent representations for the second moment using an exact, nonperturbative, statistical approach. These general results, when specialized to the weak-coupling limit, lead to a complete set of closed equations for the first two moments within the framework of an approximation corresponding to Kraichnan's direct-interaction approximation. Additional restrictions result in a self-consistent set of equations for the first two moments in the stochastic quasi-linear approximation. Finally, the technique is illustrated by considering its application to two specific physical problems: 1) Hydrodynamic turbulence; and 2) Vlasov-plasma turbulence in the presence of an external stochastic electric field. (Author)

Descriptors :   *Turbulent flow, *Stochastic processes, *Mathematical models, *Plasmas(Physics), Nonlinear systems, Electric fields, Operators(Mathematics), Hydrodynamics

Subject Categories : Fluid Mechanics
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE