Bodenschatz, Eberhard

[["dc.bibliographiccitation.artnumber","124502"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","Physical Review Letters"],["dc.bibliographiccitation.volume","116"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Xu, Haitao"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Grauer, Rainer"],["dc.date.accessioned","2020-12-10T18:25:40Z"],["dc.date.available","2020-12-10T18:25:40Z"],["dc.date.issued","2016"],["dc.description.abstract","Three-dimensional turbulent flows are characterized by a flux of energy from large to small scales, which breaks the time reversal symmetry. The motion of tracer particles, which tend to lose energy faster than they gain it, is also irreversible. Here, we connect the time irreversibility in the motion of single tracers with vortex stretching and thus with the generation of the smallest scales."],["dc.identifier.doi","10.1103/PhysRevLett.116.124502"],["dc.identifier.eissn","1079-7114"],["dc.identifier.isi","000372729200011"],["dc.identifier.issn","0031-9007"],["dc.identifier.pmid","27058081"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75783"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1079-7114"],["dc.relation.issn","0031-9007"],["dc.title","Single-Particle Motion and Vortex Stretching in Three-Dimensional Turbulent Flows"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","14"],["dc.bibliographiccitation.journal","Physical Review Letters"],["dc.bibliographiccitation.volume","119"],["dc.contributor.author","Hsu, Hsin-Fang"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Westendorf, Christian"],["dc.contributor.author","Gholami, Azam"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Tarantola, Marco"],["dc.contributor.author","Beta, Carsten"],["dc.date.accessioned","2020-12-10T18:25:44Z"],["dc.date.available","2020-12-10T18:25:44Z"],["dc.date.issued","2017"],["dc.identifier.doi","10.1103/PhysRevLett.119.148101"],["dc.identifier.eissn","1079-7114"],["dc.identifier.issn","0031-9007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75806"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Variability and Order in Cytoskeletal Dynamics of Motile Amoeboid Cells"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","035101"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Physics of Fluids"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Xu, H."],["dc.date.accessioned","2018-11-07T09:27:15Z"],["dc.date.available","2018-11-07T09:27:15Z"],["dc.date.issued","2013"],["dc.description.abstract","We describe the structure and dynamics of turbulence by the scale-dependent perceived velocity gradient tensor as supported by following four tracers, i.e., fluid particles, that initially form a regular tetrahedron. We report results from experiments in a von Kaacutermaacuten swirling water flow and from numerical simulations of the incompressible Navier-Stokes equation. We analyze the statistics and the dynamics of the perceived rate of strain tensor and vorticity for initially regular tetrahedron of size r0 from the dissipative to the integral scale. Just as for the true velocity gradient, at any instant, the perceived vorticity is also preferentially aligned with the intermediate eigenvector of the perceived rate of strain. However, in the perceived rate of strain eigenframe fixed at a given time t = 0, the perceived vorticity evolves in time such as to align with the strongest eigendirection at t = 0. This also applies to the true velocity gradient. The experimental data at the higher Reynolds number suggests the existence of a self-similar regime in the inertial range. In particular, the dynamics of alignment of the perceived vorticity and strain can be rescaled by t0, the turbulence time scale of the flow when the scale r0 is in the inertial range. For smaller Reynolds numbers we found the dynamics to be scale dependent."],["dc.identifier.doi","10.1063/1.4795547"],["dc.identifier.isi","000316951900026"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30492"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Inst Physics"],["dc.relation.issn","1070-6631"],["dc.title","Tetrahedron deformation and alignment of perceived vorticity and strain in a turbulent flow"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","2218"],["dc.bibliographiccitation.journal","Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences"],["dc.bibliographiccitation.volume","380"],["dc.contributor.author","Buaria, Dhawal"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.date.accessioned","2022-02-01T10:31:22Z"],["dc.date.available","2022-02-01T10:31:22Z"],["dc.date.issued","2022"],["dc.description.abstract","Intense fluctuations of energy dissipation rate in turbulent flows result from the self-amplification of strain rate via a quadratic nonlinearity, with contributions from vorticity (via the vortex stretching mechanism) and pressure-Hessian—which are analysed here using direct numerical simulations of isotropic turbulence on up to 12   288 3 grid points, and Taylor-scale Reynolds numbers in the range 140–1300. We extract the statistics involved in amplification of strain and condition them on the magnitude of strain. We find that strain is self-amplified by the quadratic nonlinearity, and depleted via vortex stretching, whereas pressure-Hessian acts to redistribute strain fluctuations towards the mean-field and hence depletes intense strain. Analysing the intense fluctuations of strain in terms of its eigenvalues reveals that the net amplification is solely produced by the third eigenvalue, resulting in strong compressive action. By contrast, the self-amplification acts to deplete the other two eigenvalues, whereas vortex stretching acts to amplify them, with both effects cancelling each other almost perfectly. The effect of the pressure-Hessian for each eigenvalue is qualitatively similar to that of vortex stretching, but significantly weaker in magnitude. Our results conform with the familiar notion that intense strain is organized in sheet-like structures, which are in the vicinity of, but never overlap with tube-like regions of intense vorticity due to fundamental differences in their amplifying mechanisms. This article is part of the theme issue ‘Scaling the turbulence edifice (part 1)’."],["dc.description.abstract","Intense fluctuations of energy dissipation rate in turbulent flows result from the self-amplification of strain rate via a quadratic nonlinearity, with contributions from vorticity (via the vortex stretching mechanism) and pressure-Hessian—which are analysed here using direct numerical simulations of isotropic turbulence on up to 12   288 3 grid points, and Taylor-scale Reynolds numbers in the range 140–1300. We extract the statistics involved in amplification of strain and condition them on the magnitude of strain. We find that strain is self-amplified by the quadratic nonlinearity, and depleted via vortex stretching, whereas pressure-Hessian acts to redistribute strain fluctuations towards the mean-field and hence depletes intense strain. Analysing the intense fluctuations of strain in terms of its eigenvalues reveals that the net amplification is solely produced by the third eigenvalue, resulting in strong compressive action. By contrast, the self-amplification acts to deplete the other two eigenvalues, whereas vortex stretching acts to amplify them, with both effects cancelling each other almost perfectly. The effect of the pressure-Hessian for each eigenvalue is qualitatively similar to that of vortex stretching, but significantly weaker in magnitude. Our results conform with the familiar notion that intense strain is organized in sheet-like structures, which are in the vicinity of, but never overlap with tube-like regions of intense vorticity due to fundamental differences in their amplifying mechanisms. This article is part of the theme issue ‘Scaling the turbulence edifice (part 1)’."],["dc.identifier.doi","10.1098/rsta.2021.0088"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/98843"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-517"],["dc.relation.eissn","1471-2962"],["dc.relation.issn","1364-503X"],["dc.rights.uri","https://royalsociety.org/journals/ethics-policies/data-sharing-mining/"],["dc.title","Generation of intense dissipation in high Reynolds number turbulence"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","467"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Circulation"],["dc.bibliographiccitation.lastpage","476"],["dc.bibliographiccitation.volume","120"],["dc.contributor.author","Fenton, Flavio H."],["dc.contributor.author","Luther, Stefan"],["dc.contributor.author","Cherry, Elizabeth M."],["dc.contributor.author","Otani, Niels F."],["dc.contributor.author","Krinsky, Valentin"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Gilmour, Robert F."],["dc.date.accessioned","2022-03-01T11:43:52Z"],["dc.date.available","2022-03-01T11:43:52Z"],["dc.date.issued","2009"],["dc.identifier.doi","10.1161/CIRCULATIONAHA.108.825091"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/102862"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-531"],["dc.relation.eissn","1524-4539"],["dc.relation.issn","0009-7322"],["dc.title","Termination of Atrial Fibrillation Using Pulsed Low-Energy Far-Field Stimulation"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","043004"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","New Journal of Physics"],["dc.bibliographiccitation.volume","21"],["dc.contributor.author","Buaria, Dhawal"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Yeung, P. K."],["dc.date.accessioned","2019-07-09T11:51:27Z"],["dc.date.available","2019-07-09T11:51:27Z"],["dc.date.issued","2019"],["dc.description.abstract","Fully turbulent flows are characterized by intermittent formation of very localized and intense velocity gradients. These gradients can be orders of magnitude larger than their typical value and lead to many unique properties of turbulence. Using direct numerical simulations of the Navier–Stokes equations with unprecedented small-scale resolution, we characterize such extreme events over a significant range of turbulence intensities, parameterized by the Taylor-scale Reynolds number (Rl). Remarkably, we find the strongest velocity gradients to empirically scale as t l - Rb K 1 , with b »  0.775 0.025,where tK is theKolmogorov time scale (with its inverse, t-K1, being the rms of velocity gradient fluctuations). Additionally, we observe velocity increments across very small distances r  h,where η is theKolmogorov length scale, to be as large as the rms of the velocity fluctuations. Both observations suggest that the smallest length scale in the flow behaves as h l R-a,with a = b - 1 2 , which is at odds with predictions from existing phenomenological theories.Wefind that extreme gradients are arranged in vortex tubes, such that strain conditioned on vorticity grows on average slower than vorticity, approximately as a power law with an exponent g < 1, which weakly increaseswith Rl.Using scaling arguments,we get b = (2 - g)-1,which suggests that βwould also slowly increasewith Rl.We conjecture that approaching themathematical limit of infinite Rl, strain and vorticity would scale similarly resulting in g = 1and hence extreme events occurring at a scale h l R-1/2 corresponding to b = 1."],["dc.identifier.doi","10.1088/1367-2630/ab0756"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/16127"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59948"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation","info:eu-repo/grantAgreement/EC/FP7/312778/EU//EUHIT"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","CC BY 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0/"],["dc.subject.ddc","530"],["dc.title","Extreme velocity gradients in turbulent flows"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","079901"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Physics of Fluids"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Falkovich, Gregory"],["dc.contributor.author","Xu, H."],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.contributor.author","Biferale, Luca"],["dc.contributor.author","Boffetta, Guido"],["dc.contributor.author","Lanotte, Alessandra S."],["dc.contributor.author","Toschi, Federico"],["dc.date.accessioned","2018-11-07T09:08:22Z"],["dc.date.available","2018-11-07T09:08:22Z"],["dc.date.issued","2012"],["dc.identifier.doi","10.1063/1.4738734"],["dc.identifier.isi","000308406000055"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26017"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Inst Physics"],["dc.relation.issn","1070-6631"],["dc.title","On Lagrangian single-particle statistics (vol 24, 055102, 2012)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","041006"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Physical Review X"],["dc.bibliographiccitation.volume","4"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Xu, H."],["dc.contributor.author","Boffetta, Guido"],["dc.contributor.author","Falkovich, Gregory"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.date.accessioned","2018-11-07T09:33:40Z"],["dc.date.available","2018-11-07T09:33:40Z"],["dc.date.issued","2014"],["dc.description.abstract","In statistically homogeneous turbulent flows, pressure forces provide the main mechanism to redistribute kinetic energy among fluid elements, without net contribution to the overall energy budget. This holds true in both two-dimensional (2D) and three-dimensional (3D) flows, which show fundamentally different physics. As we demonstrate here, pressure forces act on fluid elements very differently in these two cases. We find in numerical simulations that in 3D pressure forces strongly accelerate the fastest fluid elements, and that in 2D this effect is absent. In 3D turbulence, our findings put forward a mechanism for a possibly singular buildup of energy, and thus may shed new light on the smoothness problem of the solution of the Navier-Stokes equation in 3D."],["dc.identifier.doi","10.1103/PhysRevX.4.041006"],["dc.identifier.fs","606696"],["dc.identifier.isi","000343773800001"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11554"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/32019"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation","info:eu-repo/grantAgreement/EC/FP7/312778/EU//EUHIT"],["dc.relation.issn","2160-3308"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","CC BY 3.0"],["dc.title","Redistribution of Kinetic Energy in Turbulent Flows"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","Physical Review Letters"],["dc.bibliographiccitation.volume","119"],["dc.contributor.author","Prabhakaran, Prasanth"],["dc.contributor.author","Weiss, Stephan"],["dc.contributor.author","Krekhov, Alexei"],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.date.accessioned","2020-12-10T18:25:44Z"],["dc.date.available","2020-12-10T18:25:44Z"],["dc.date.issued","2017"],["dc.identifier.doi","10.1103/PhysRevLett.119.128701"],["dc.identifier.eissn","1079-7114"],["dc.identifier.issn","0031-9007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75804"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Can Hail and Rain Nucleate Cloud Droplets?"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","709"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Nature Physics"],["dc.bibliographiccitation.lastpage","712"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Xu, H."],["dc.contributor.author","Pumir, Alain"],["dc.contributor.author","Bodenschatz, Eberhard"],["dc.date.accessioned","2018-11-07T08:52:45Z"],["dc.date.available","2018-11-07T08:52:45Z"],["dc.date.issued","2011"],["dc.description.abstract","The disorganized fluctuations of turbulence are crucial in the transport of particles or chemicals(1,2) and could play a decisive role in the formation of rain in clouds(3), the accretion process in protoplanetary disks(4), and how animals find their mates or prey(5,6). These and other examples(7) suggest a yet-to-be-determined unifying structure of turbulent flows(8,9). Here, we unveil an important ingredient of turbulence by taking the perspective of an observer who perceives its world with respect to three distant neighbours all swept by the flow. The time evolution of the observer's world can be decomposed into rotation and stretching. We show that, in this Lagrangian frame, the axis of rotation aligns with the initially strongest stretching direction, and that the dynamics can be understood by the conservation of angular momentum. This 'pirouette effect' thus appears as an important structural component of turbulence, and elucidates the mechanism for small-scale generation in turbulence."],["dc.identifier.doi","10.1038/NPHYS2010"],["dc.identifier.isi","000294485400018"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22245"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Nature Publishing Group"],["dc.relation.issn","1745-2473"],["dc.title","The pirouette effect in turbulent flows"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]