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A fundamental relation in Lagrangian Kolmogorov theory is concerned with inertial range scaling of the second-order velocity structure function over intermediate time lags at sufficiently high Reynolds numbers. Significant theoretical…

Fluid Dynamics · Physics 2026-03-24 Rohini Uma-Vaideswaran , P. K. Yeung

It is often asserted in the literature that one should expect positive autocorrelation for random walk Metropolis-Hastings (RWMH), especially if the typical proposal step-size is small relative to the variability in the target density. In…

Probability · Mathematics 2026-01-28 James Allen Fill , Svante Janson

We present measurements of the scale (bin-size) dependence of event-wise mean transverse momentum $<p_{t}>$ fluctuations for Au-Au collisions at $\sqrt{s_{NN}} = 200$ GeV simulated with the Hijing-1.37 Monte Carlo. We invert those scale…

High Energy Physics - Phenomenology · Physics 2009-12-15 Qingjun Liu , Duncan J. Prindle , Thomas A. Trainor

The velocity fluctuations for point vortex models are studied for the {\alpha}-turbulence equations, which are characterized by a fractional Laplacian relation between active scalar and the streamfunction. In particular, we focus on the…

Fluid Dynamics · Physics 2019-09-11 Giovanni Conti , Gualtiero Badin

The causal connection between congestions and velocity changes at different locations induces various statistical features, which we identify and measure in detail. We carry out an empirical analysis of large-scale traffic data on a local…

Physics and Society · Physics 2024-10-10 Shanshan Wang , Michael Schreckenberg , Thomas Guhr

The character of turbulence depends on where it develops. Turbulence near boundaries, for instance, is different than in a free stream. To elucidate the differences between flows, it is instructive to vary the structure of turbulence…

Fluid Dynamics · Physics 2019-05-01 Kevin P. Griffin , Nathaniel J. Wei , Eberhard Bodenschatz , Gregory P. Bewley

Early-warning indicators (increase of autocorrelation and variance) are commonly applied to time series data to try and detect tipping points of real-world systems. The theory behind these indicators originates from approximating the…

Dynamical Systems · Mathematics 2016-09-26 Paul Ritchie , Jan Sieber

Radial velocity fluctuations on the plane of the sky are a powerful tool for studying the turbulent dynamics of emission line regions. We conduct a systematic statistical analysis of the H alpha velocity field for a diverse sample of 9 H II…

Astrophysics of Galaxies · Physics 2023-06-14 J. García-Vázquez , William J. Henney , H. O. Castañeda

We present the results of a numerical investigation of three-dimensional decaying turbulence with statistically homogeneous and anisotropic initial conditions. We show that at large times, in the inertial range of scales: (i) isotropic…

Chaotic Dynamics · Physics 2007-05-23 L. Biferale , G. Boffetta , A. Celani , A. Lanotte , F. Toschi , M. Vergassola

Velocity increments over a distance r and turbulent energy dissipation on a box of size r are well described by the multifractal models of fully developed turbulence. These quantities and models however, do not involve time-correlations and…

chao-dyn · Physics 2008-02-03 R. Lima , R. Vilela Mendes

In an attempt to determine the outer scale of turbulence driven by localized sources, such as supernova explosions in the interstellar medium, we consider a forcing function given by the gradient of gaussian profiles localized at random…

Astrophysics · Physics 2007-05-23 Antony J. Mee , Axel Brandenburg

The presence of long-ranged correlations in a fluid undergoing uniform shear flow is investigated. An exact relation between the density autocorrelation function and the density-mometum correlation function implies that the former must…

Statistical Mechanics · Physics 2009-11-07 James F. Lutsko , J. W. Dufty

High Reynolds numbers Navier-Stokes equations are believed to break self-similarity concerning both spatial and temporal properties: correlation functions of different orders exhibit distinct decorrelation times and anomalous spatial…

Fluid Dynamics · Physics 2012-10-04 Luca Biferale , Enrico Calzavarini , Federico Toschi

Sequences with low aperiodic autocorrelation are used in communications and remote sensing for synchronization and ranging. The autocorrelation demerit factor of a sequence is the sum of the squared magnitudes of its autocorrelation values…

Information Theory · Computer Science 2024-08-19 Daniel J. Katz , Miriam E. Ramirez

We investigate spatial and temporal cross-correlations between streamwise and normal velocity components in three shear flows: a low-dimensional model for vortex-streak interactions, direct numerical simulations for a nearly homogeneous…

Chaotic Dynamics · Physics 2009-11-11 A. Jachens , J. Schumacher , B. Eckhardt , K. Knobloch , H. H. Fernholz

We propose a novel estimator of the autocorrelation function in presence of missing observations. We establish the consistency, the asymptotic normality, and we derive deviation bounds for various classes of weakly dependent stationary time…

Methodology · Statistics 2010-04-22 Natalia Bahamonde , Paul Doukhan , Eric Moulines

We observe oscillatory decay in the two-point, non-equal time, velocity correlation function of homogeneous, isotropic turbulence. We found this through a direct numerical simulation (DNS) of the three dimensional Navier-Stokes ($3-D$ NS)…

Chaotic Dynamics · Physics 2007-05-23 Anirban Sain

We study the statistical properties of helicity in direct numerical simulations of fully developed homogeneous and isotropic turbulence and in a class of turbulence shell models. We consider correlation functions based on combinations of…

Fluid Dynamics · Physics 2017-02-08 Ganapati Sahoo , Massimo De Pietro , Luca Biferale

Correlation coefficients play a pivotal role in quantifying linear relationships between random variables. Yet, their application to time series data is very challenging due to temporal dependencies. This paper introduces a novel approach…

Methodology · Statistics 2024-01-09 Johan Medrano , Abderrahmane Kheddar , Sofiane Ramdani

A quantity of interest to characterise continuous-valued stochastic processes is the differential entropy rate. The rate of convergence of many properties of LRD processes is slower than might be expected, based on the intuition for…

Information Theory · Computer Science 2021-11-02 Andrew Feutrill , Matthew Roughan