The roles of shear and cross-correlations on the fluctuation levels in simple stochastic models. Revision

Technical Report · Wed Nov 03 00:00:00 EST 1999

DOI:https://doi.org/10.2172/751203· OSTI ID:751203

Krommes, J A

Highly simplified models of random flows interacting with background microturbulence are analyzed. In the limit of very rapid velocity fluctuations, it is shown rigorously that the fluctuation level of a passively advected scalar is not controlled by the rms shear. In a model with random velocities dependent only on time, the level of cross-correlations between the flows and the background turbulence regulates the saturation level. This effect is illustrated by considering a simple stochastic-oscillator model, both exactly and with analysis and numerical solutions of the direct-interaction approximation. Implications for the understanding of self-consistent turbulence are discussed briefly.

• Research Organization: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 751203
• Report Number(s): PPPL-3377Revised; TRN: US0000897
• Resource Relation: Other Information: PBD: 3 Nov 1999
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION
PLASMA SIMULATION
TIME DEPENDENCE
TURBULENCE
STOCHASTIC PROCESSES
SHEAR
PLASMA DRIFT