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Atmospheric Turbulence (AT) correction is a challenging restoration task as it consists of two distortions: geometric distortion and spatially variant blur. Diffusion models have shown impressive accomplishments in photo-realistic image…

Computer Vision and Pattern Recognition · Computer Science 2023-07-28 Xijun Wang , Santiago López-Tapia , Aggelos K. Katsaggelos

The traditional wave equation models wave propagation in an ideal conducting medium. For characterizing the wave propagation in inhomogeneous media with frequency dependent power-law attenuation, the space-time fractional wave equation…

Numerical Analysis · Mathematics 2017-12-22 Yajing Li , Yejuan Wang , Weihua Deng

We consider Taylor dispersion for tracer particles in micro-fluidic planar channels with strong confinement. In this context, the channel walls modify the local diffusivity tensor and also interactions between the tracer particles and the…

Fluid Dynamics · Physics 2021-08-12 Arthur Alexandre , Thomas Guérin , David S. Dean

The `local scaling' hypothesis, first introduced by Nieuwstadt two decades ago, describes the turbulence structure of stable boundary layers in a very succinct way and is an integral part of numerous local closure-based numerical weather…

Atmospheric and Oceanic Physics · Physics 2016-08-16 Sukanta Basu , Fernando Porté-Agel , Efi Foufoula-Georgiou , Jean-François Vinuesa , Markus Pahlow

The random motion of molecules in living cells has consistently been reported to deviate from standard Brownian motion, a behavior coined as ``anomalous diffusion''. Fluorescence Correlation Spectroscopy (FCS) is a powerful method to…

Quantitative Methods · Quantitative Biology 2024-07-18 Nathan Quiblier , Jan-Michael Rye , Pierre Leclerc , Henri Truong , Abdelkrim Hannou , Laurent Héliot , Hugues Berry

We study the generalized Langevin equation approach to anomalous diffusion for a harmonic oscillator and a free particle driven by different forms of internal noises, such as power-law-correlated and distributed-order noises that fulfil…

Statistical Mechanics · Physics 2023-09-01 Z. Tomovski , K. Gorska , T. Pietrzak , R. Metzler , T. Sandev

Temporal data such as time series can be viewed as discretized measurements of the underlying function. To build a generative model for such data we have to model the stochastic process that governs it. We propose a solution by defining the…

Machine Learning · Computer Science 2023-05-22 Marin Biloš , Kashif Rasul , Anderson Schneider , Yuriy Nevmyvaka , Stephan Günnemann

The immense computational cost of simulating turbulence has motivated the use of machine learning approaches for super-resolving turbulent flows. A central challenge is ensuring that learned models respect physical symmetries, such as…

With the development of high performance computer and experimental technology, the study of turbulence has accumulated a large number of high fidelity data. However, few general turbulence knowledge has been found from the data. So we use…

Fluid Dynamics · Physics 2024-06-17 ZhongXin Yang , XiangLin Shan , WeiWei Zhang

Relative dispersion in a neutrally stratified planetary boundary layer (PBL) is investigated by means of Large-Eddy Simulations (LES). Despite the small extension of the inertial range of scales in the simulated PBL, our Lagrangian…

Fluid Dynamics · Physics 2009-11-10 G. Gioia , G. Lacorata , E. P. Marques Filho , A. Mazzino , U. Rizza

Synchronization of turbulence in channel flow is investigated using continuous data assimilation. The flow is unknown within a region of the channel. Beyond this region the velocity field is provided, and is directly prescribed in the…

Fluid Dynamics · Physics 2022-06-22 Mengze Wang , Tamer A. Zaki

Dynamical systems driven by a general L\'evy stable noise are considered. The inertia is included and the noise, represented by a generalised Ornstein-Uhlenbeck process, has a finite relaxation time. A general linear problem (the additive…

Statistical Mechanics · Physics 2012-02-15 Tomasz Srokowski

A formalism is introduced to describe a number of physical processes that may break down the coherence of a matter wave over a characteristic length scale l. In a second-quantized description, an appropriate master equation for a set of…

Quantum Physics · Physics 2015-06-26 Julio Gea-Banacloche

Based on recent developments in physics-informed deep learning and deep hidden physics models, we put forth a framework for discovering turbulence models from scattered and potentially noisy spatio-temporal measurements of the probability…

Fluid Dynamics · Physics 2018-11-20 Maziar Raissi , Hessam Babaee , Peyman Givi

How locally injected turbulence, spreads in space is investigated with direct numerical simulations. We consider a turbulent flow in a long channel generated by a forcing that is localised in space. The forcing is such that it does not…

Fluid Dynamics · Physics 2023-07-18 Alexandros Alexakis

A phenomenological model for the dissipation of scalar fluctuations due to the straining by the fluid motion is proposed in this letter. An explicit equation is obtained for the time evolution of the probability distribution function of a…

Fluid Dynamics · Physics 2015-06-26 Antoine Venaille , Joel Sommeria

Molecules in dense environments, such as biological cells, are subjected to forces that fluctuate both in time and in space. While spatial fluctuations are captured by Lifson-Jackson-Zwanzig's model of "diffusion in a rough potential", and…

Statistical Mechanics · Physics 2025-06-04 Dmitrii E. Makarov , Peter Sollich

We report a first-principles study of static transport of localized waves in quasi-one-dimensional open media. We found that such transport, dominated by disorder-induced resonant transmissions, displays novel diffusive behavior. Our…

Disordered Systems and Neural Networks · Physics 2015-05-18 Chu-Shun Tian , Sai-Kit Cheung , Zhao-Qing Zhang

White paper: The aim of this work is to apply and analyze machine learning methods for uncertainty quantification of turbulence models. In this work we investigate the classical and data-driven variants of the eigenspace perturbation…

Fluid Dynamics · Physics 2022-11-04 Marcel Matha , Karsten Kucharczyk

We study a turbulence closure model in which the fractional Laplacian $(-\Delta)^\alpha$ of the velocity field represents the turbulence diffusivity. We investigate the energy spectrum of the model by applying Pao's energy transfer theory.…

Numerical Analysis · Mathematics 2016-11-17 Max Gunzburger , Nan Jiang , Feifei Xu
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