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We consider smooth flows preserving a smooth invariant measure, or, equivalently, locally Hamiltonian flows on compact orientable surfaces and show that almost every such locally Hamiltonian flow with only simple saddles has singular…

Dynamical Systems · Mathematics 2025-05-20 Krzysztof Frączek , Adam Kanigowski , Corinna Ulcigrai

Recently, J. Streets and G. Tian introduced a natural way to evolve an almost-K\"ahler manifold called the symplectic curvature flow, in which the metric, the symplectic structure and the almost-complex structure are all evolving. We study…

Symplectic Geometry · Mathematics 2015-05-25 Jorge Lauret , Cynthia Will

In this note, we consider the entropy of unit area translation surfaces in the $SL(2, \mathbb R)$ orbits of square tiled surfaces that are the union of squares, where the singularities occur at the vertices and the singularities have a…

Dynamical Systems · Mathematics 2022-07-04 Paul Colognese , Mark Pollicott

An ideal compressible fluid is considered, with an equilibrium density being a given function of coordinates due to presence of some static external forces. The slow flows in such system, which do not disturb the density, are investigated…

Fluid Dynamics · Physics 2009-11-06 V. P. Ruban

Error estimates are proved for an evolving surface finite element semi-discretization for anisotropic mean curvature flow of closed surfaces. For the geometric surface flow, a system coupling the anisotropic evolution law to parabolic…

Numerical Analysis · Mathematics 2025-08-05 Klaus Deckelnick , Harald Garcke , Balázs Kovács

In this article, we exhibit certain linking properties of periodic orbits of $C^{1+\alpha}$ flows with positive topological entropy on closed 3-manifolds M. It is shown that any such flow contains a link L of periodic orbits and a horseshoe…

Dynamical Systems · Mathematics 2024-01-25 Matthias Meiwes

We prove that oriented and standard shadowing properties are equivalent for topological flows on closed surfaces with the nonwandering set consisting of the finite number of critical elements (i.e., singularities or closed orbits).…

Dynamical Systems · Mathematics 2023-02-07 Sogo Murakami

In this paper, we study the flow of closed, starshaped hypersurfaces in $\mathbb{R}^{n+1}$ with speed $r^\alpha\sigma_2^{1/2},$ where $\sigma_2^{1/2}$ is the normalized square root of the scalar curvature, $\alpha\geq 2,$ and $r$ is the…

Differential Geometry · Mathematics 2020-08-14 Ling Xiao

Recent developments in turbulence are focused on the effect of large scale anisotropy on the small scale statistics of velocity increments. According to Kolmogorov, isotropy is recovered in the large Reynolds number limit as the scale is…

Chaotic Dynamics · Physics 2009-11-11 C. M. Casciola , P. Gualtieri , B. Jacob , R. Piva

Consider the motion of a material point of unit mass in a central field determined by a homogeneous potential of the form $(-1/r^{\alpha})$, $\alpha>0,$ where $r$ being the distance to the centre of the field. Due to the singularity at…

Mathematical Physics · Physics 2009-10-01 Manuele Santoprete , Cristina Stoica

In this paper we prove that the generic singularities of mean curvature flow of closed embedded surfaces in $\mathbb R^3$ modeled by closed self-shrinkers with multiplicity has multiplicity one. Together with the previous result by…

Differential Geometry · Mathematics 2021-07-26 Ao Sun

The famous Rokhlin Problem asks whether mixing implies higher order mixing. So far, all the known examples of zero entropy, mixing dynamical systems enjoy a variant of the mixing via shearing mechanism. In this paper we introduce the notion…

Dynamical Systems · Mathematics 2024-10-18 Adam Kanigowski , Davide Ravotti

We derive general depth-integrated model equations for overland flows featuring the evolution of suspended sediment that may be eroded from or deposited onto the underlying topography ('morphodynamics'). The resulting equations include…

Fluid Dynamics · Physics 2023-06-29 Jake Langham , Mark J. Woodhouse , Andrew J. Hogg , Luke T. Jenkins , Jeremy C. Phillips

We consider inviscid flow with isentropic coefficient greater than one. For flow along smooth infinite protruding corners we attempt to impose a nonzero limit for velocity at infinity at the upstream wall. We prove that the problem does not…

Analysis of PDEs · Mathematics 2018-05-23 Volker Elling

We consider a $C^{1,\alpha}$ smooth flow in $\mathbb{R}^n$ which is "strongly monotone" with respect to a cone $C$ of rank $k$, a closed set that contains a linear subspace of dimension $k$ and no linear subspaces of higher dimension. We…

Dynamical Systems · Mathematics 2019-05-17 Lirui Feng , Yi Wang , Jianhong Wu

We report on the decay of a passive scalar in chaotic mixing protocols where the wall of the vessel is rotated, or a net drift of fluid elements near the wall is induced at each period. As a result the fluid domain is divided into a central…

Soft Condensed Matter · Physics 2010-07-06 Emmanuelle Gouillart , Jean-Luc Thiffeault , Olivier Dauchot

We give a uniform lower bound for the polynomial complexity of all Reeb flows on the spherization (S*M,\xi) over a closed manifold. Our measure for the dynamical complexity of Reeb flows is slow volume growth, a polynomial version of…

Dynamical Systems · Mathematics 2013-07-30 Urs Frauenfelder , Clémence Labrousse , Felix Schlenk

Surface growth models may give rise to unstable growth with mound formation whose tipical linear size L increases in time. In one dimensional systems coarsening is generally driven by an attractive interaction between domain walls or kinks.…

Statistical Mechanics · Physics 2007-05-23 Alessandro Torcini , Paolo Politi

Let $M\subset {\mathbf R}^{m+1}$ be a smooth, closed, codimension-one self-shrinker (for mean curvature flow) with nontrivial $k^{\rm th}$ homology. We show that the entropy of $M$ is greater than or equal to the entropy of a round…

Differential Geometry · Mathematics 2024-03-26 Or Hershkovits , Brian White

Steady fluid flows have very special topology. In this paper we describe necessary and sufficient conditions on the vorticity function of a 2D ideal flow on a surface with or without boundary, for which there exists a steady flow among…

Symplectic Geometry · Mathematics 2015-11-19 Anton Izosimov , Boris Khesin