Perlekar, Prasad and Ray, Samriddhi Sankar and Mitra, Dhrubaditya and Pandit, Rahul (2011) Persistence Problem in Two-Dimensional Fluid Turbulence. In: Physical Review Letters, 106 (5).
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We present a natural framework for studying the persistence problem in two-dimensional fluid turbulence by using the Okubo-Weiss parameter Lambda to distinguish between vortical and extensional regions. We then use a direct numerical simulation of the two-dimensional, incompressible Navier-Stokes equation with Ekman friction to study probability distribution functions (PDFs) of the persistence times of vortical and extensional regions by employing both Eulerian and Lagrangian measurements. We find that, in the Eulerian case, the persistence-time PDFs have exponential tails; by contrast, this PDF for Lagrangian particles, in vortical regions, has a power-law tail with an exponent theta = 2.9 +/- 0.2.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to The American Physical Society.|
|Date Deposited:||24 Mar 2011 12:06|
|Last Modified:||24 Mar 2011 12:06|
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