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Generation of Lagrangian intermittency in turbulence by a self-similar mechanism

Title data

Wilczek, Michael ; Xu, Haitao ; Ouellette, Nicholas T. ; Friedrich, Rudolf ; Bodenschatz, Eberhard:
Generation of Lagrangian intermittency in turbulence by a self-similar mechanism.
In: New Journal of Physics. Vol. 15 (2013) . - No. 055015.
ISSN 1367-2630
DOI: https://doi.org/10.1088/1367-2630/15/5/055015

Abstract in another language

Intermittency, i.e., extreme fluctuations at small scales, causes the deviation of turbulence statistics from Kolmogorov\textquotesingles 1941 theoretical predictions. Intermittency effects are especially strong for Lagrangian statistics. Our understanding of how Lagrangian intermittency manifests, however, is still elusive. Here, we study the Lagrangian intermittency in the framework of an exact, yet unclosed probability density function (PDF) equation. Combining this theoretical approach with data from experiments and simulations, no a priori phenomenological assumptions about the structure or properties of the flow have to be made. In this description, the non-self-similar evolution of the velocity increment PDF is determined at all scales by a single function, which is accessible through data from experiments and simulations. This \textquotesingleintermittency generating function\textquotesingle arises from the dependence of the acceleration of a fluid element on its velocity history, thereby coupling different scales of turbulent motion. Empirically, we find that the intermittency generating function has a simple, approximately self-similar form, which has the surprising implication that Lagrangian intermittency—the absence of self-similarity in the Lagrangian velocity increment statistics—is driven by a self-similar mechanism. The simple form of the intermittency generating function furthermore allows us to formulate a simple model parametrization of the velocity increment PDFs.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics I > Chair Theoretical Physics I - Univ.-Prof. Dr. Michael Wilczek
Profile Fields > Advanced Fields > Nonlinear Dynamics
Result of work at the UBT: No
DDC Subjects: 500 Science > 530 Physics
Date Deposited: 18 Feb 2022 08:34
Last Modified: 18 Feb 2022 08:34
URI: https://eref.uni-bayreuth.de/id/eprint/67563