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We study the Korteweg-de Vries-type equation dt u=-dx(dx^2 u+f(u)-B(t,x)u), where B is a small and bounded, slowly varying function and f is a nonlinearity. Many variable coefficient KdV-type equations can be rescaled into this equation. We…

Mathematical Physics · Physics 2007-05-23 S. I. Dejak , B. L. G. Jonsson

Answering the question of V.I. Oseledets, we present a random variable $\xi$ such that the sum $\xi(x)+a\xi(y)$ has a singular distribution for a set of parameters $a$ dense in $(1, +\infty)$, but for another dense set of parameters, this…

Dynamical Systems · Mathematics 2022-02-21 Valery V. Ryzhikov

The time-fractional diffusion-wave equation is revisited, where the time derivative is of order $2 \nu$ and $0 < \nu \le 1$. The behaviour of the equation is "diffusion-like" (respectively, "wave-like") when $0 < \nu \le \frac{1}{2}$…

Analysis of PDEs · Mathematics 2021-10-25 Marianito R. Rodrigo

The observation of fluid-like behavior in nucleus-nucleus, proton-nucleus and high-multiplicity proton-proton collisions motivates systematic studies of how different measurements approach their fluid-dynamic limit. We have developed…

High Energy Physics - Phenomenology · Physics 2020-11-11 Aleksi Kurkela , Seyed Farid Taghavi , Urs Achim Wiedemann , Bin Wu

We study the steady states and dynamics of a thin film-type equation with non-conserved mass in one dimension. The evolution equation is a nonlinear fourth-order degenerate parabolic PDE motivated by a model of volatile viscous fluid films…

Analysis of PDEs · Mathematics 2019-10-29 Hangjie Ji , Thomas P. Witelski

Direct Numerical Simulation is performed of the forced Navier-Stokes equation in four spatial dimensions. Well equilibrated, long time runs at sufficient resolution were obtained to reliably measure spectral quantities, the velocity…

Fluid Dynamics · Physics 2020-08-18 Arjun Berera , Richard D. J. G. Ho , Daniel Clark

We investigate the shallow flow of viscous fluid into and out of a channel whose gap width increases as a power-law ($x^n$), where $x$ is the downstream axis. The fluid flows slowly, while injected at a rate in the form of $t^\alpha$, where…

Fluid Dynamics · Physics 2023-12-13 M-S. Liu , H. E. Huppert

Hydrodynamics provides a universal description of the emergent collective dynamics of vastly different many-body systems, based solely on their symmetries and conservation laws. Here we harness this universality, encoded in the…

Statistical Mechanics · Physics 2025-12-16 P. I. Hurtado , J. J. del Pozo , P. L. Garrido

In this letter we present a measurement of the phase-space density distribution (PSDD) of ultra-cold \Rb atoms performing 1D anomalous diffusion. The PSDD is imaged using a direct tomographic method based on Raman velocity selection. It…

Atomic Physics · Physics 2017-08-16 Gadi Afek , Jonathan Coslovsky , Arnaud Courvoisier , Oz Livneh , Nir Davidson

The problem of front propagation in flowing media is addressed for laminar velocity fields in two dimensions. Three representative cases are discussed: stationary cellular flow, stationary shear flow, and percolating flow. Production terms…

Chaotic Dynamics · Physics 2009-10-31 M. Abel , A. Celani , D. Vergni , A. Vulpiani

We study anomalous diffusion for one-dimensional systems described by a generalized Langevin equation. We show that superdiffusion can be classified in slow superdiffusion and fast superdiffusion. For fast superdiffusion we prove that the…

Statistical Mechanics · Physics 2007-05-23 Ismael V. L. Costa , Rafael Morgado , Marcos V. B. T. Lima , Fernando A. Oliveira

In this paper, we consider an inverse space-dependent source problem for a time-fractional diffusion equation. To deal with the ill-posedness of the problem, we transform the problem into an optimal control problem with total variational…

Optimization and Control · Mathematics 2025-01-15 Bin Fan

We introduce a general framework for defining context-dependent time distributions in quantum systems using projective measurements. The time-of-flow (TF) distribution, derived from population transfer rates into a measurement subspace,…

Quantum Physics · Physics 2025-11-17 Mathieu Beau

We study a 2D potential flow of an ideal fluid with a free surface with decaying conditions at infinity. By using the conformal variables approach, we study a particular solution of Euler equations having a pair of square-root branch points…

Fluid Dynamics · Physics 2022-12-14 A. I. Dyachenko , S. A. Dyachenko , V. E. Zakharov

We develop a weakly intrusive framework to simulate the propagation of uncertainty in solutions of generic hyperbolic partial differential equation systems on graph-connected domains with nodal coupling and boundary conditions. The method…

Numerical Analysis · Mathematics 2022-04-14 Svetlana Tokareva , Anatoly Zlotnik , Vitaliy Gyrya

We use confocal microscopy to directly visualize the spatial fluctuations in fluid flow through a three-dimensional porous medium. We find that the velocity magnitudes and the velocity components both along and transverse to the imposed…

Soft Condensed Matter · Physics 2013-08-07 Sujit S. Datta , Harry Chiang , T. S. Ramakrishnan , David A. Weitz

In this article a two-sided variable coefficient fractional diffusion equation (FDE) is investigated, where the variable coefficient occurs outside of the fractional integral operator. Under a suitable transformation the variable…

Numerical Analysis · Mathematics 2018-11-05 Xiangcheng Zheng , V. J. Ervin , Hong Wang

We consider reaction-diffusion equations $\partial_tu=\Delta u+f(u)$ in the whole space $\mathbb{R}^N$ and we are interested in the large-time dynamics of solutions ranging in the interval $[0,1]$, with general unbounded initial support.…

Analysis of PDEs · Mathematics 2022-07-14 François Hamel , Luca Rossi

We give some new results related to the directional short-time Fourier transform (DSTFT) and extend them on the spaces $\mathcal K_{1}(\mathbb R^{n})$ and $\mathcal K_{1}({\mathbb R})\widehat{\otimes}\mathcal U(\mathbb C^n)$ and their…

Functional Analysis · Mathematics 2017-08-28 Sanja Atanasova , Stevan Pilipovic , Katerina Saneva

We prove that, in the flat torus and in any dimension, the volume-preserving mean curvature flow and the surface diffusion flow, starting $C^{1,1}-$close to a strictly stable critical set of the perimeter $E$, exist for all times and…

Differential Geometry · Mathematics 2025-05-23 Daniele De Gennaro , Antonia Diana , Andrea Kubin , Anna Kubin