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The change of the effective dimension of spacetime with the probed scale is a universal phenomenon shared by independent models of quantum gravity. Using tools of probability theory and multifractal geometry, we show how dimensional flow is…

High Energy Physics - Theory · Physics 2012-08-16 Gianluca Calcagni

Starting from the classical formulation of the weak turbulence theory in a density stratified fluid, we derive a simplified version of the kinetic equation of internal gravity wave turbulence. This equation allows us to uncover scaling laws…

Fluid Dynamics · Physics 2024-02-01 Nicolas Lanchon , Pierre-Philippe Cortet

Two dimensional passive scalar turbulence is studied by means of a k-space diffusion model based on a third order differential approximation. This simple description of local nonlinear interactions in Fourier space is shown to present a…

Fluid Dynamics · Physics 2019-10-08 Pierre Morel , Shaokang Xu , Özgür D. Gürcan

The anomalous scaling phenomena of three-dimensional passive scalar turbulence are studied using high resolution direct numerical simulation. The inertial range scaling exponents of the passive scalar increment and the scalar dissipation…

chao-dyn · Physics 2009-10-30 Shiyi Chen , Nianzheng Cao

We propose a new class of generative diffusion models, called functional diffusion. In contrast to previous work, functional diffusion works on samples that are represented by functions with a continuous domain. Functional diffusion can be…

Computer Vision and Pattern Recognition · Computer Science 2023-11-28 Biao Zhang , Peter Wonka

Turbulence constitutes an exceptionally complex and irregular flow phenomenon that manifests in liquids, gases, and plasma, making it ubiquitous in both natural processes and engineering applications. Given the relatively modest…

Fluid Dynamics · Physics 2025-07-08 Ziqi Ji , Penghao Duan , Gang Du

We establish global-in-time existence results for thermodynamically consistent reaction-(cross-)diffusion systems coupled to an equation describing heat transfer. Our main interest is to model species-dependent diffusivities, while at the…

Analysis of PDEs · Mathematics 2022-02-11 Julian Fischer , Katharina Hopf , Michael Kniely , Alexander Mielke

We construct and study global solutions for the 3-dimensional incompressible MHD systems with arbitrary small viscosity. In particular, we provide a rigorous justification for the following dynamical phenomenon observed in many contexts:…

Analysis of PDEs · Mathematics 2016-03-29 Ling-Bing He , Li Xu , Pin Yu

The scattering of three-dimensional inertia-gravity waves by a turbulent geostrophic flow leads to the redistribution of their action through what is approximately a diffusion process in wavevector space. The corresponding diffusivity…

Atmospheric and Oceanic Physics · Physics 2023-03-06 Michael R. Cox , Hossein A. Kafiabad , Jacques Vanneste

Simulations of turbulent flows in 3D are one of the most expensive simulations in computational fluid dynamics (CFD). Many works have been written on surrogate models to replace numerical solvers for fluid flows with faster, learned,…

Fluid Dynamics · Physics 2024-03-18 Marten Lienen , David Lüdke , Jan Hansen-Palmus , Stephan Günnemann

Motivated by previous work on kinetic energy cascades in the ocean and atmosphere, we develop a spatio-temporal spectral transfer tool that can be used to study scales of variability in generalized dynamical systems. In particular, we use…

In natural settings, intermittent dynamics are ubiquitous and often arise from a coupling between external driving and spatial heterogeneities. A well-known example is the generation of transient, turbulent puffs of fluid through a pipe…

Adaptation and Self-Organizing Systems · Physics 2020-07-01 Guram Gogia , Wentao Yu , Justin C. Burton

Chaotic flows drive mixing and efficient transport in fluids, as well as the associated beautiful complex patterns familiar to us from our every day life experience. Generating such flows at small scales where viscosity takes over is highly…

Chaotic Dynamics · Physics 2017-10-09 Eldad Afik , Victor Steinberg

We study a quantum particle propagating through a ``quantum mechanically chaotic'' background, described by parametric random matrices with only short range spatial correlations. The particle is found to exhibit turbulent-like diffusion…

chao-dyn · Physics 2009-10-30 Dimitri Kusnezov , Aurel Bulgac , Gui Do Dang

The three-dimensional equations for the compressible flow of liquid crystals are considered. An initial-boundary value problem is studied in a bounded domain with large data. The existence and large-time behavior of a global weak solution…

Analysis of PDEs · Mathematics 2015-05-30 Dehua Wang , Cheng Yu

We investigate the long time behavior of a passive particle evolving in a one-dimensional diffusive random environment, with diffusion constant $D$. We consider two cases: (a) The particle is pulled forward by a small external constant…

Statistical Mechanics · Physics 2018-04-16 François Huveneers

Three-dimensional miscible Rayleigh--Taylor (RT) turbulence at small Atwood number and at Prandtl number one is investigated by means of high resolution direct numerical simulations of the Boussinesq equations. RT turbulence is a…

Chaotic Dynamics · Physics 2015-05-19 G. Boffetta , A. Mazzino , S. Musacchio , L. Vozella

Identification and extraction of vortical structures and of waves in a disorganised flow is a mayor challenge in the study of turbulence. We present a study of the spatio-temporal behavior of turbulent flows in the presence of different…

Fluid Dynamics · Physics 2015-11-09 P. Clark di Leoni , P. J. Cobelli , P. D. Mininni

We consider a wide class of approximate models of evolution of singular distributions of vorticity in three dimensional incompressible fluids and we show that they have global smooth solutions. The proof exploits the existence of suitable…

Mathematical Physics · Physics 2007-05-23 L. C. Berselli , M. Gubinelli

In this paper we are concerned with the global existence of smooth solutions to the turbulent flow equations for compressible flows in $\mathbb{R}^3$. The global well-posedness is proved under the condition that the initial data are close…

Analysis of PDEs · Mathematics 2012-04-10 Dongfen Bian , Boling Guo