In:
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, The Royal Society, Vol. 380, No. 2226 ( 2022-06-27)
Abstract:
We investigate the spatio-temporal structure of the most likely configurations realizing extremely high vorticity or strain in the stochastically forced three-dimensional incompressible Navier–Stokes equations. Most likely configurations are computed by numerically finding the highest probability velocity field realizing an extreme constraint as solution of a large optimization problem. High-vorticity configurations are identified as pinched vortex filaments with swirl, while high-strain configurations correspond to counter-rotating vortex rings. We additionally observe that the most likely configurations for vorticity and strain spontaneously break their rotational symmetry for extremely high observable values. Instanton calculus and large deviation theory allow us to show that these maximum likelihood realizations determine the tail probabilities of the observed quantities. In particular, we are able to demonstrate that artificially enforcing rotational symmetry for large strain configurations leads to a severe underestimate of their probability, as it is dominated in likelihood by an exponentially more likely symmetry-broken vortex-sheet configuration. This article is part of the theme issue ‘Mathematical problems in physical fluid dynamics (part 2)’.
Type of Medium:
Online Resource
ISSN:
1364-503X
,
1471-2962
DOI:
10.1098/rsta.2021.0051
Language:
English
Publisher:
The Royal Society
Publication Date:
2022
detail.hit.zdb_id:
208381-4
detail.hit.zdb_id:
1462626-3
SSG:
11
SSG:
5,1
SSG:
5,21
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