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Rotationally coherent Lagrangian vortices are formed by tubes of deforming fluid elements that complete equal bulk material rotation relative to the mean rotation of the deforming fluid volume. We show that initial positions of such tubes…

流体动力学 · 物理学 2016-05-04 George Haller , Alireza Hadjighasem , Mohammad Farazmand , Florian Huhn

This paper examines the mechanisms of coherent structure interactions in spatially evolving turbulent free shear layers at different values of the velocity ratio parameter {\lambda}=$(U_1-U_2)/(U_1+U_2)$, where $U_1$ and $U_2 (\leq U_1)$…

流体动力学 · 物理学 2015-11-19 Saikishan Suryanarayanan , Roddam Narasimha

Spiral waves are considered to be one of the potential mechanisms that maintains complex arrhythmias such as atrial and ventricular fibrillation. The aim of the present study was to quantify the complex dynamics of spiral waves as the…

斑图形成与孤子 · 物理学 2018-07-03 Daniel Sohn , Konstantinos N. Aronis , Hiroshi Ashikaga

We report experimental results on the three dimensional Lagrangian acceleration in highly turbulent flows. Tracer particles are tracked optically using four silicon strip detectors from high energy physics that provide high temporal and…

流体动力学 · 物理学 2009-11-10 Nicolas Mordant , Alice M. Crawford , Eberhard Bodenschatz

Understanding blood transport in cardiovascular flows is important for managing patients with cardiovascular disease. In this study, three-dimensional Lagrangian coherent structures have been extracted for the first time in both healthy…

医学物理 · 物理学 2024-01-05 Wissam Abdallah , Ahmed Darwish , Julio Garcia , Lyes Kadem

Deterministic and probabilistic tools from nonlinear dynamics are used to assess enduring near-surface Lagrangian aspects of the Malvinas Current. The deterministic tools are applied on a multi-year record of velocities derived from…

大气与海洋物理 · 物理学 2020-02-19 FJ Beron-Vera , N. Bodnariuk , M. Saraceno , MJ Olascoaga , C Simionato

Moving structures have been detected in coronal bright points and in a solar flare in active regions, which were bi-directional, symmetrical, simultaneous, and quasi-periodic (Ning & Guo 2014; Ning 2016; Li et al. 2016a). They could be…

太阳与恒星天体物理 · 物理学 2022-06-01 Dong Li

The close connection of magnetic field structure on the one hand and observable features of complex ARs with high flare efficiency on the other one is investigated in frames of so-called dynamic classification of flaring magnetic…

天体物理学 · 物理学 2007-05-23 R. N. Ikhsanov , Yu. V. Marushin

Densely packed coronal loops are rooted in plages in the vicinity of active regions on the Sun. The photospheric magnetic features underlying these plages are patches of mostly unidirectional magnetic field extending several arcsec on the…

太阳与恒星天体物理 · 物理学 2019-04-03 L. P. Chitta , A. R. C. Sukarmadji , L. Rouppe van der Voort , H. Peter

Convolutional autoencoders are used to deconstruct the changing dynamics of two-dimensional Kolmogorov flow as $Re$ is increased from weakly chaotic flow at $Re=40$ to a chaotic state dominated by a domain-filling vortex pair at $Re=400$.…

流体动力学 · 物理学 2024-11-20 Jacob Page , Joe Holey , Michael P. Brenner , Rich R. Kerswell

We investigate exact nonlinear waves on surfaces locally approximating the rotating sphere for two-dimensional inviscid incompressible flow. Our first system corresponds to a beta-plane approximation at the equator and the second to a gamma…

流体动力学 · 物理学 2024-11-20 Nick Pizzo , Rick Salmon

Using a recent catalogue of extragalactic Faraday rotation derived from the NRAO VLA Sky Survey we have found an agreement between Faraday rotation structure and the HI emission structure of a High Velocity Cloud (HVC) associated with the…

星系天体物理 · 物理学 2015-05-20 N. M. McClure-Griffiths , G. J. Madsen , B. M. Gaensler , D. McConnell , D. H. F. M. Schnitzeler

In the present paper, we study transport properties of coherent vortices. These structures are formed by tubes of fluid parcels that complete similar material rotation. Here, we demonstrate that time $t_0$ positions of such physical…

流体动力学 · 物理学 2021-12-16 Anass El Aouni , Arthur Vidard

We analyze a solar active region observed by the Hinode CaII H line using the time-distance helioseismology technique, and infer wave-speed perturbation structures and flow fields beneath the active region with a high spatial resolution.…

太阳与恒星天体物理 · 物理学 2014-11-20 Junwei Zhao , Alexander G. Kosovichev , Takashi Sekii

We analyze large-scale patterns in three-dimensional turbulent convection in a horizontally extended square convection cell by Lagrangian particle trajectories calculated in direct numerical simulations. A simulation run at a Prandtl number…

流体动力学 · 物理学 2018-11-19 Christiane Schneide , Ambrish Pandey , Kathrin Padberg-Gehle , Jörg Schumacher

A dynamical system framework is used to describe transport processes in plasmas embedded in a magnetic field. For periodic systems with one degree of freedom the Poincar\'e map provides a splitting of the phase space into regions where…

等离子体物理 · 物理学 2015-07-28 M. V. Falessi , F. Pegoraro , T. J. Schep

Particle-laden effects in high-speed flows require a coupled Euler and Lagrangian prediction technique with varying fidelity of thermochemical models, depending on the simulation conditions of interest. This requirement makes the…

流体动力学 · 物理学 2025-12-23 Hyeon Woo Nam , Tae Woong Jeong , Sung Min Jo

The Helioseismic and Magnetic Imager provides 45 s cadence intensity images and 720 s cadence vector magnetograms. These unprecedented high-cadence and high-resolution data give us a unique opportunity to study the change of photospheric…

太阳与恒星天体物理 · 物理学 2015-06-18 Shuo Wang , Chang Liu , Na Deng , Haimin Wang

We study the development of coherent structures in local simulations of the magnetorotational instability in accretion discs in regimes of on-off intermittency. In a previous paper [Chian et al., Phys. Rev. Lett. 104, 254102 (2010)], we…

太阳与恒星天体物理 · 物理学 2015-06-23 Rodrigo A. Miranda , Erico L. Rempel , Abraham C. -L. Chian

A nonlinear force-free solution is constructed for the coronal magnetic field in NOAA solar active region AR 10953 based on a photospheric vector magnetogram derived from Hinode satellite observations on 30 April 2007, taking into account…

太阳与恒星天体物理 · 物理学 2015-05-20 M. S. Wheatland , K. D. Leka