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The complex interaction between turbulence and the free surface in boundary layer shear flow created by a vertical surface-piercing wall is considered. A laboratory-scale device was built that utilizes a surface-piercing stainless steel…

Fluid Dynamics · Physics 2017-03-29 Nathan Washuta , Naeem Masnadi , James H. Duncan

Turbulent dynamics generate random fluctuations in density and velocity in the Interstellar Medium (ISM) of spiral and dwarf galaxies. Observationally, H~{\sc i} 21-cm radiation provides a good probe of these stochastic processes and helps…

Astrophysics of Galaxies · Physics 2018-05-30 Meera Nandakumar

This paper introduces a couple of new time-frequency transforms, designed to adapt their scale to specific features of the analyzed function. Such an adaptation is implemented via so-called focus functions, which control the window scale as…

Classical Analysis and ODEs · Mathematics 2024-06-19 Pierre Warion , Bruno Torrésani

Recent studies provide evidence for the multi-scale nature of magnetic turbulence in the plasma sheet. Wavelet methods represent modern time series analysis techniques suitable for the description of statistical characteristics of…

Space Physics · Physics 2016-09-08 W. Baumjohann , R. Nakamura , A. Runov , M. Volwerk , T. L. Zhang , A. Balogh

Direct numerical simulations of turbulent flow in a channel with one rigid and one viscoelastic wall are performed. An Eulerian-Eulerian model is adopted with a level-set approach to identify the fluid-compliant material interface. Focus is…

Fluid Dynamics · Physics 2021-11-03 Amir Esteghamatian , Joseph Katz , Tamer A. Zaki

The effect of grid resolution on large eddy simulation (LES) of wall-bounded turbulent flow is investigated. A channel flow simulation campaign involving systematic variation of the streamwise ($\Delta x$) and spanwise ($\Delta z$) grid…

Fluid Dynamics · Physics 2018-05-23 Saleh Rezaeiravesh , Mattias Liefvendahl

Response details are presented of small-scale Helmholtz resonators excited by grazing turbulent boundary layer flow. A particular focus lies on scaling of the resonance, in relation to the spatio-temporal characteristics of the near-wall…

Fluid Dynamics · Physics 2023-08-16 Giulio Dacome , Renko Siebols , Woutijn J. Baars

Turbulence exhibits significant velocity fluctuations even if the scale is much larger than the scale of the energy supply. Since any spatial correlation is negligible, these large-scale fluctuations have many degrees of freedom and are…

Fluid Dynamics · Physics 2015-05-20 H. Mouri , A. Hori , Y. Kawashima , K. Hashimoto

A number of micro-scale biological flows are characterized by spatio-temporal chaos. These include dense suspensions of swimming bacteria, microtubule bundles driven by motor proteins, and dividing and migrating confluent layers of cells. A…

Fluid Dynamics · Physics 2017-08-02 Javier Urzay , Amin Doostmohammadi , Julia M. Yeomans

We develop a theory of turbulence of weak random gravity waves on surface of deep water in which the main nonlinear process at high-frequency part of the spectrum is a nonlocal interaction with a strong low-frequency component. The latter…

Fluid Dynamics · Physics 2024-09-05 A. O. Korotkevich , S. V. Nazarenko , Y. Pan , J. Shatah

We utilize the externally forced linearized Navier-Stokes equations to study the receptivity of pre-transitional boundary layers to persistent sources of stochastic excitation. Stochastic forcing is used to model the effect of free-stream…

Fluid Dynamics · Physics 2019-09-09 Wei Ran , Armin Zare , M. J. Philipp Hack , Mihailo R. Jovanović

Opposition-control of the energetic cycle of near wall streaks in wall-bounded turbulence, using numerical approaches, has shown promise for drag reduction. For practical implementation, opposition control is only realizable if there is a…

The variance and spectra of wall-normal velocities are investigated for direct numerical simulations of turbulent flow in a channel, pipe, and zero-pressure-gradient boundary layer across a decade of friction Reynolds numbers. Spectra along…

Fluid Dynamics · Physics 2026-04-22 Michael Heisel , Rahul Deshpande , Gabriel G. Katul

Scaling of the mean velocity profiles has been studied by many researchers, since it provides a template of universal dynamical patterns across a range of Reynolds numbers. Various normalization schemes have been shown in the past, some…

Fluid Dynamics · Physics 2024-12-04 T. -W. Lee

We apply a formalism of nonextensive statistical mechanics to experimental wall turbulence data, for the first time to our knowledge. Wind tunnel data for velocity differences a streamwise distance $r$ apart are compared to the prediction…

Fluid Dynamics · Physics 2014-02-11 Simen Å Ellingsen , Per-Åge Krogstad

Financial spillovers in interconnected systems, such as global banking networks, require tools that capture temporal and frequency dynamics, while incorporating the underlying network topology. While current network time series models are…

Methodology · Statistics 2026-04-07 Cristian F. Jiménez-Varón , Marina I. Knight

Most data processing techniques, applied to biomedical and sociological time series, are only valid for random fluctuations that are stationary in time. Unfortunately, these data are often non stationary and the use of techniques of…

Data Analysis, Statistics and Probability · Physics 2009-11-10 M. Ignaccolo , P. Allegrini , P. Grigolini , P. Hamilton , B. J. West

The search for solutions to the theory of weakly non-linear internal gravity wave turbulence is an active research topic. It is notably stimulated by the fact that this regime could drive fine-scale ocean dynamics for which the…

Fluid Dynamics · Physics 2025-09-01 Nicolas Lanchon , Samuel Boury , Pierre-Philippe Cortet

We compute the frequency spectrum of turbulent superfluid vortex density fluctuations and obtain the same Kolmogorov scaling which has been observed in a recent experiment in Helium-4. We show that the scaling can be interpreted in terms of…

Statistical Mechanics · Physics 2011-08-05 Andrew W. Baggaley , Carlo F. Barenghi

The observability of the flow field away from the wall in turbulent channel flow is studied using only wall observations. Reconstructions are generated from noiseless but limited wall data using linear stochastic estimation, with emphasis…

Fluid Dynamics · Physics 2019-11-13 Miguel P. Encinar , Javier Jiménez