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We consider two continuous-time generalizations of conservative random walks introduced in [J.Englander and S.Volkov (2022)], an orthogonal and a spherically-symmetrical one; the latter model is known as {\em random flights}. For both…

Probability · Mathematics 2025-02-19 Satyaki Bhattacharya , Stanislav Volkov

We experimentally test the effects of tilting a turbulent Rayleigh-B{\'e}nard convection cell on the dynamics of the large-scale circulation (LSC) orientation $\theta_0$. The probability distribution of $\theta_0$ is measured, and used to…

Fluid Dynamics · Physics 2020-07-30 Dandan Ji , Kunlun Bai , Eric Brown

We establish exact inequalities for the structure-function scaling exponents of a passively advected scalar in both the inertial-convective and viscous-convective ranges. These inequalities involve the scaling exponents of the velocity…

chao-dyn · Physics 2009-10-28 Gregory L. Eyink

In light of the emergence of big data, I have advocated and argued for a paradigm shift from Tobler's law to scaling law, from Euclidean geometry to fractal geometry, from Gaussian statistics to Paretian statistics, and - more importantly -…

Databases · Computer Science 2020-09-04 Bin Jiang

It is well-known that fractal signals appear in many fields of science. LAN and WWW traces, wireless traffic, VBR resources, etc. are among the ones with this behavior in computer networks traffic flows. An important question in these…

Signal Processing · Electrical Eng. & Systems 2021-05-10 G. Millán

In the initial conditions of the $3 + 1$ formalism for numerical relativity, the transverse and trace-free (TT) part of the extrinsic curvature plays a key role. We know that TT tensors possess two degrees of freedom per space point.…

General Relativity and Quantum Cosmology · Physics 2016-03-21 Rory Conboye , Niall Ó Murchadha

We compute the spectra and fluxes of the velocity and temperature fields in Rayleigh-B\'{e}nard convection in turbulent regime for a wide range of Prandtl numbers using pseudo-spectral simulations on $512^3$ grids. Our spectral and flux…

Fluid Dynamics · Physics 2010-05-21 Pankaj Kumar Mishra , Mahendra K. Verma

Small-scale fluctuations of different tracers of the interstellar the medium can be used to study the nature of turbulence in astrophysical scales. Of these, the `continuum' emission traces the fluctuations integrated along the line of…

Astrophysics of Galaxies · Physics 2019-01-30 Samir Choudhuri , Nirupam Roy

From a database of direct numerical simulations of homogeneous and isotropic turbulence, generated in periodic boxes of various sizes, we extract the spherically symmetric part of moments of velocity increments and first verify the…

Fluid Dynamics · Physics 2020-05-20 Kartik P. Iyer , Katepalli R. Sreenivasan , P. K. Yeung

We used the time correlation of shadowgraph images to determine the angle $\Theta$ of the horizontal component of the plume velocity above (below) the center of the bottom (top) plate of a cylindrical Rayleigh-B\'enard cell of aspect ratio…

Chaotic Dynamics · Physics 2009-11-10 Denis Funfschilling , Guenter Ahlers

Turbulent suspensions of heavy particles in incompressible flows have gained much attention in recent years. A large amount of work focused on the impact that the inertia and the dissipative dynamics of the particles have on their dynamical…

Chaotic Dynamics · Physics 2009-11-13 Jeremie Bec , Massimo Cencini , Rafaela Hillerbrand , Konstantin Turitsyn

In this paper, we investigated the statistical differences between active and passive scalars in isotropic compressible turbulence. In the inertial range, the kinetic energy and scalar have the Kolmogorov spectra, and the Kolmogorov and…

Fluid Dynamics · Physics 2015-05-12 Qionglin Ni , Yipeng Shi , Shiyi Chen

Since the pioneering work of Richardson in 1926, later refined by Batchelor and Obukhov in 1950, it is predicted that the rate of separation of pairs of fluid elements in turbulent flows with initial separation at inertial scales, grows…

Fluid Dynamics · Physics 2023-07-19 Mickael Bourgoin

An operator $T\in B(H)$ is said to satisfy property ($UW${\scriptsize \it{E}}) if the complement in the approximate point spectrum of the essential approximate point spectrum coincides with the isolated eigenvalues of the spectrum. Via the…

Quantum Physics · Physics 2024-08-13 Sinan Qiu , Lining Jiang

A solvable turbulent model is used to predict both the structure of the boundary layer and the scaling laws in thermal convection. The transport of heat depends on the interplay between the thermal, viscous and integral scales of…

Fluid Dynamics · Physics 2015-05-28 B. Dubrulle

Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux $\Pi_u$, we demonstrate that for stably stratified flows, the kinetic energy spectrum $E_u(k) \sim k^{-11/5}$, the entropy spectrum…

Fluid Dynamics · Physics 2015-06-22 Abhishek Kumar , Anando G. Chatterjee , Mahendra K. Verma

We constrain the velocity power spectrum shape parameter $\Gamma$ in linear theory using the nine bulk-flow and shear moments estimated from four recent peculiar velocity surveys. For each survey, a likelihood function for $\Gamma$ was…

Astrophysics · Physics 2008-11-26 Richard Watkins , Hume A. Feldman

The direction and magnitude of energy transfer between turbulence scale brought about by external forcing on a turbulent boundary layer are uncovered through the bispectrum, bicoherence, and biphase. The bispectrum is a third-order,…

Fluid Dynamics · Physics 2025-11-18 Clayton P. Byers , Subrahmanyam Duvvuri

Recently, Shete et al. [Phys. Rev. Fluids 7, 024601 (2022)] explored the characteristics of passive scalars in the presence of a uniform mean gradient, mixed by stationary isotropic turbulence. They concluded that at high Reynolds and…

Fluid Dynamics · Physics 2023-09-06 Dhawal Buaria , Katepalli R. Sreenivasan

In this paper, the problem of assessing the twistability of a given bona fide cross-spectral density is tackled for the class of Schell-model sources, whose shift-invariant degree of coherence is represented by a real and symmetric…

Optics · Physics 2025-01-07 Riccardo Borghi