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Algorithmic exploration of dominant terms around hairpin vortices generated during boundary-layer transition under Free-Stream Turbulence

Kazuo Matsuura
2019 International Journal of Environmental Impacts Management Mitigation and Recovery  
A new method that evaluates dominant local dynamics by skeletonization, mathematical term decomposition and the re-combination of a reduced number of dominant terms around the skeleton points is proposed  ...  to clarify the dynamics of hairpin vortices generated during the boundary-layer transition under free-stream turbulence (FST).  ...  When a set of NFD terms, LAV terms and SC terms in W k are denoted as S S S NFD W LAV W SC W k k k , , , , , , respectively, the hierarchical relationship Σ Σ Σ NFD W LAV W SC W  ... 
doi:10.2495/ei-v3-n1-66-80 fatcat:tyqacsggfbgybgph2k55iev7iq

Swirling around filaments: are large-scale structure vortices spinning up dark haloes?

C. Laigle, C. Pichon, S. Codis, Y. Dubois, D. Le Borgne, D. Pogosyan, J. Devriendt, S. Peirani, S. Prunet, S. Rouberol, A. Slyz, T. Sousbie
2014 Monthly notices of the Royal Astronomical Society  
On large scales, adiabatic/cooling hydrodynamical simulations display the same vorticity in the gas as in the dark matter.  ...  excess of probability of 20 per cent to have the angle between vorticity and filaments direction lower than 60 degrees relative to random orientations.  ...  The contours of minimal vorticity are defined as being the descending 2-manifolds of the skeleton calculated on the norm of the vorticity field.  ... 
doi:10.1093/mnras/stu2289 fatcat:5xyyldf4bjdcloo5juylvedoym

Vortex and Strain Skeletons in Eulerian and Lagrangian Frames

Jan Sahner, Tino Weinkauf, Nathalie Teuber, Hans-Christian Hege
2007 IEEE Transactions on Visualization and Computer Graphics  
By considering the extremal features of those quantities, we define the notions of a vortex and a strain skeleton in a hierarchical manner: the collection of maximal 0D, 1D and 2D structures assemble the  ...  vortex skeleton; the minimal structures identify the strain skeleton.  ...  Figure 8 shows how the vortex and strain skeletons of Q can be used for hierarchical feature display, considering a subregion of the cylinder dataset as an example.  ... 
doi:10.1109/tvcg.2007.1053 pmid:17622681 fatcat:4v6j3nqwybfffnr5ncdspd2yte

Detecting vorticity filaments using wavelet analysis: About the statistical contribution of vorticity filaments to intermittency in swirling turbulent flows

S. Roux, J.F. Muzy, A. Arneodo
1999 European Physical Journal B : Condensed Matter Physics  
Swirling turbulent flows display intermittent pressure drops associated with intense vorticity filaments.  ...  In particular, the skeleton of the CWT defined by the wavelet transform modulus maxima (WTMM) [73, 74] was shown to contain all the information concerning the hierarchical distribution of the singularities  ...  in the (x, a) half-plane enlightens the hierarchical organization of the singularities.  ... 
doi:10.1007/s100510050694 fatcat:e7fzsiwhvbglffo22oh7guxr2i

Page 5579 of Mathematical Reviews Vol. , Issue 88j [page]

1988 Mathematical Reviews  
Hierarchical levels of mechanisms with the same complexity (isocomplex mechanisms) are specified.  ...  Rotating auto-wave vortices determine the ac- tion regime of an active medium.  ... 

Extraction of Coherent Structures from Natural and Actuated Flows [chapter]

Jens Kasten, Tino Weinkauf, Christoph Petz, Ingrid Hotz, Bernd R. Noack, Hans-Christian Hege
2010 Active Flow Control II  
One key enabler are Galilean invariant flow quantities based on pressure, acceleration, vorticity and velocity Jacobians.  ...  Applying hierarchical vortex extraction, cf. Fig. 8, the pairing of vortices directly behind the airfoil is clearly highlighted.  ...  The λ 2 measure is used as an indicator for vortices. In Fig. 6(a) , the raw feature skeleton resulting from the MS cancellation can be seen. The lines are color-coded with λ 2 .  ... 
doi:10.1007/978-3-642-11735-0_24 fatcat:24rwmlggsbc67b5bbtf4jmwkju

Rivers of Gas I.: Unveiling The Properties of High Redshift Filaments [article]

Marius Ramsøy, Adrianne Slyz, Julien Devriendt, Clotilde Laigle, Yohan Dubois
2021 arXiv   pre-print
When feedback is included the gas temperature and vorticity fields are strongly perturbed, hindering such a measurement in the vicinity of the galaxy.  ...  In both gas and DM, temperature and vorticity sharply drop at the edge of filaments, providing an excellent way to constrain the outer filament radius.  ...  3 and 5) and, as a result, it not easy to stack individual vorticity profiles obtained for each skeleton segment.  ... 
arXiv:2101.00844v2 fatcat:5jgatxi2jzagbg3ttyzuxkurxa

Randomized methods to characterize large-scale vortical flow network [article]

Zhe Bai, N. Benjamin Erichson, Muralikrishnan Gopalakrishnan Meena, Kunihiko Taira, Steven L. Brunton
2019 arXiv   pre-print
We demonstrate the effective use of randomized methods for linear algebra to perform network-based analysis of complex vortical flows.  ...  Network theoretic approaches can reveal the connectivity structures among a set of vortical elements and analyze their collective dynamics.  ...  These communities have an important physical interpretation in vortical flow networks, hierarchically identifying and organizing vortex cores within the flow.  ... 
arXiv:1909.00535v1 fatcat:ictu4yegjfe7pircrtiqg5aj6y

Climate Science, Waves and PDEs for the Tropics [chapter]

Andrew J. Majda
2012 Abel Symposia  
Such hierarchical organized structures that generate the MJO as their envelope are the focus of current observational initiatives and modeling studies [52] , and there is a general lack of theoretical  ...  Although theory and simulation of the MJO remain difficult challenges, they are guided by the generally accepted, fundamental features of the MJO (i.e., the MJOs skeleton) on intraseasonal/planetary scales  ... 
doi:10.1007/978-3-642-25361-4_12 fatcat:hu7u7h5rgnc2nozkshfhhpnhey

Quantitative classification of vortical flows based on topological features using graph matching

Paul S. Krueger, Michael Hahsler, Eli V. Olinick, Sheila H. Williams, Mohammadreza Zharfa
2019 Proceedings of the Royal Society A  
fields is quantified by finding the best match (minimum difference) in weights of matched graph edges under relevant constraints on the properties of the edge vertices, and flows are classified using hierarchical  ...  Vortical flow patterns generated by swimming animals or flow separation (e.g. behind bluff objects such as cylinders) provide important insight to global flow behaviour such as fluid dynamic drag or propulsive  ...  of vortices (e.g.  ... 
doi:10.1098/rspa.2018.0897 pmid:31534418 pmcid:PMC6735483 fatcat:donxfxk6qja7pc4n5olqlveeau

Randomized methods to characterize large-scale vortical flow networks

Zhe Bai, N. Benjamin Erichson, Muralikrishnan Gopalakrishnan Meena, Kunihiko Taira, Steven L. Brunton, Fang-Bao Tian
2019 PLoS ONE  
We demonstrate the effective use of randomized methods for linear algebra to perform network-based analysis of complex vortical flows.  ...  Network theoretic approaches can reveal the connectivity structures among a set of vortical elements and analyze their collective dynamics.  ...  These communities have an important physical interpretation in vortical flow networks, hierarchically identifying and organizing vortex cores within the flow.  ... 
doi:10.1371/journal.pone.0225265 pmid:31738778 pmcid:PMC6860431 fatcat:gl3oqlypozatna4zolpwq53zoq

Shape Memory of Human Red Blood Cells

Thomas M. Fischer
2004 Biophysical Journal  
This disadvantage was overcome by a protocol of hierarchical preshear periods (see Preshear at Room Temperature).  ...  The second is usually called membrane skeleton. For shortness we refer to it by skeleton.  ... 
doi:10.1016/s0006-3495(04)74378-7 pmid:15111443 pmcid:PMC1304195 fatcat:6jzywcne3ngmtdwmmym4fjxefe

The skeleton of tropical intraseasonal oscillations

A. J. Majda, S. N. Stechmann
2009 Proceedings of the National Academy of Sciences of the United States of America  
., its "skeleton") on intraseasonal/planetary scales: (i) the peculiar dispersion relation of dω/dk ≈ 0, (ii) the slow phase speed of ≈5 m/s, and (iii) the horizontal quadrupole vortex structure.  ...  The key premise of the model is that modulations of synoptic scale wave activity are induced by low-level moisture preconditioning on planetary scales, and they drive the "skeleton" of the MJO through  ...  Matsuno-Gill models show a basic Kelvin-Rossby wave structure for the MJO (39, 40) , although it lacks the horizontal quadrupole vortices.  ... 
doi:10.1073/pnas.0903367106 pmid:19423670 pmcid:PMC2678888 fatcat:wt7vy5gwvbggdd5nakckzn73ua

TURBULENCE IN THE INTERGALACTIC MEDIUM: SOLENOIDAL AND DILATATIONAL MOTIONS AND THE IMPACT OF NUMERICAL VISCOSITY

Weishan Zhu, Long-long Feng, Yinhua Xia, Chi-Wang Shu, Qiusheng Gu, Li-Zhi Fang
2013 Astrophysical Journal  
We find that (1) The vortical motion grows rapidly since z=2, and reaches ∼ 10 km/s -90 km/s at z=0.  ...  Meanwhile, the small-scale compressive ratio r_CS drops from 0.84 to 0.47, indicating comparable vortical and compressive motions at present. (2) Power spectra of the solenoidal velocity possess two regimes  ...  Properties of Shocks The shocks formed during the hierarchical structure formation can effectively produce vorticity via the baroclinity term (Kida & Orzsag 1990; Ryu et al. 2008; ZFF2010) , and hence  ... 
doi:10.1088/0004-637x/777/1/48 fatcat:6l4cvfev5ndifg4l7qshjpsa5y

Feature Mining Paradigms for Scientific Data [chapter]

Ming Jiang, Tat-Sang Choy, Sameep Mehta, Matt Coatney, Steve Barr, Kaden Hazzard, David Richie, Srinivasan Parthasarathy, Raghu Machiraju, David Thompson, John Wilkins, Boyd Gatlin
2003 Proceedings of the 2003 SIAM International Conference on Data Mining  
[28] , they used conical frusta to "flesh out" the skeleton graph representation of vortices. For modeling the shape of vortical regions, this approach is not ideal.  ...  Figure 8 : 8 Elliptical frustum Figure 9 : 9 Adaptive and hierarchical shape characterization of the vortices in the blunt fin data set: (a) level 1, (b) level 2, and (c) level 4.  ... 
doi:10.1137/1.9781611972733.2 dblp:conf/sdm/JiangCMCBHRPMTWG03 fatcat:vdyzq5ceqbf5tpao65anfvqsjy
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