Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· arXiv e-print (arXiv:nlin/0404016)
· References in the article
· Citations to the Article (19) (Citation History)
· Refereed Citations to the Article
· Reads History
· HEP/Spires Information
·
· Translate This Page
Title:
Diffusion of passive scalar in a finite-scale random flow
Authors:
Schekochihin, Alexander A.; Haynes, Peter H.; Cowley, Steven C.
Affiliation:
AA(DAMTP/CMS, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom), AB(DAMTP/CMS, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom), AC(Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547, USA; Plasma Physics Group, Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2BW, United Kingdom)
Publication:
Physical Review E, vol. 70, Issue 4, id. 046304 (PhRvE Homepage)
Publication Date:
10/2004
Origin:
APS
PACS Keywords:
Fluctuation phenomena random processes noise and Brownian motion, Chaotic dynamics
DOI:
10.1103/PhysRevE.70.046304
Bibliographic Code:
2004PhRvE..70d6304S

Abstract

We consider a solvable model of the decay of scalar variance in a single-scale random velocity field. We show that if there is a separation between the flow scale kflow-1 and the box size kbox-1 , the decay rate λ∝(kbox/kflow)2 is determined by the turbulent diffusion of the box-scale mode. Exponential decay at the rate λ is preceded by a transient powerlike decay (the total scalar variance ˜t-5/2 if the Corrsin invariant is zero, t-3/2 otherwise) that lasts a time t˜1/λ . Spectra are sharply peaked at k=kbox . The box-scale peak acts as a slowly decaying source to a secondary peak at the flow scale. The variance spectrum at scales intermediate between the two peaks (kbox≪k≪kflow) is ˜k+ak2+…(a>0) . The mixing of the flow-scale modes by the random flow produces, for the case of large Péclet number, a k-1+δ spectrum at k≫kflow , where δ∝λ is a small correction. Our solution thus elucidates the spectral make up of the “strange mode,” combining small-scale structure and a decay law set by the largest scales.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
  New!

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints