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The log-normal type of turbulence energy spectral function, derived from the maximum entropy principle, is shown to be parameterizable in terms of root turbulence variables including the Reynolds number. The spectral function is first…

Fluid Dynamics · Physics 2021-02-24 T. -W. Lee

Direct numerical simulations (DNS) of turbulent channel flows up to $Re_{\tau} \approx 1000$ are conducted to investigate the three-dimensional (consisting of streamwise wavenumber, spanwise wavenumber and frequency) spectrum of wall…

Fluid Dynamics · Physics 2022-03-14 Bowen Yang , Zixuan Yang

This study investigates the impact of molecular thermal fluctuations on compressible decaying isotropic turbulence using the unified stochastic particle (USP) method, encompassing both two-dimensional (2D) and three-dimensional (3D)…

Fluid Dynamics · Physics 2023-07-03 Qihan Ma , Chunxin Yang , Song Chen , Kaikai Feng , Ziqi Cui , Jun Zhang

Data available in literature from direct numerical simulations of two-dimensional turbulent channels by Lee & Moser (2015), Bernardini et al. (2014), Yamamoto and Tsuji (2018) and Orlandi et al. (2015) in a large range of Reynolds number…

Fluid Dynamics · Physics 2019-01-08 Paolo Orlandi

We investigate flows interacting with a square and a fractal shape multi-scale structures in the compressible regime for Mach numbers at subsonic and supersonic upstream conditions using large-eddy-simulations (LES). We also aim at…

Fluid Dynamics · Physics 2020-10-28 Omar Es-Sahli , Adrian Sescu , Mohammed Z. Afsar , Oliver R. H. Buxton

Direct numerical simulation of open channel flow over a geometrically rough wall has been performed at a bulk Reynolds number of approximately 2900. The wall consisted of a layer of spheres in a square arrangement. Two cases have been…

Fluid Dynamics · Physics 2013-01-28 Clemens Chan-Braun , Manuel García-Villalba , Markus Uhlmann

The flapping states of a flexible fiber fully coupled to a three-dimensional turbulent flow are investigated via state-of-the-art numerical methods. Two distinct flapping regimes are predicted by the phenomenological theory recently…

Fluid Dynamics · Physics 2019-04-29 Marco Edoardo Rosti , Stefano Olivieri , Arash A. Banaei , Luca Brandt , Andrea Mazzino

Harmonic oscillations of the walls of a turbulent plane channel flow are studied by direct numerical simulations to improve our understanding of the physical mechanism for skin-friction drag reduction. The simulations are carried out at…

Fluid Dynamics · Physics 2017-04-26 Pierre Ricco , Claudio Ottonelli , Yosuke Hasegawa , Maurizio Quadrio

A new velocity scale is derived that yields a Reynolds number independent profile for the streamwise turbulent fluctuations in the near-wall region of wall bounded flows for $y^+<25$. The scaling demonstrates the important role played by…

Fluid Dynamics · Physics 2024-02-06 Marcus Hultmark , Alexander J. Smits

We present results from a systematic numerical study of structural properties of an unforced, incompressible, homogeneous, and isotropic three-dimensional turbulent fluid with an initial energy spectrum that develops a cascade of kinetic…

Statistical Mechanics · Physics 2009-11-11 Chirag Kalelkar

The addition of particles to turbulent flows changes the underlying mechanism of turbulence and leads to turbulence modulation. Different temporal and spatial scales for both phases make it challenging to understand turbulence modulation…

Fluid Dynamics · Physics 2023-05-24 Naveen Rohilla , Siddhi Arya , Partha Sarathi Goswami

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

The emergence of large-scale spatial modulations of turbulent channel flow, as the Reynolds number is decreased, is addressed numerically using the framework of linear stability analysis. Such modulations are known as the precursors of…

Three different porous substrates (with different pore sizes, s, and permeabilities, K) are used to examine their effect on the structure of boundary layer flow over them. The flow is characterised with single-point hot-wire measurements as…

Fluid Dynamics · Physics 2024-02-06 Prateek Jaiswal , Bharathram Ganapathisubramani

We observe electro-hydrodynamically driven turbulent flows at low Reynolds numbers in a two-fluid emulsion consisting of micron-scale droplets. In the presence of electric fields, the droplets produce interacting hydrodynamic flows which…

Soft Condensed Matter · Physics 2021-02-22 Atul Varshney , Mayur Sathe , Shankar Ghosh , Anand Yethiraj , S. Bhattacharya , J. B. Joshi

We study the global, i.e. radially averaged, high Reynolds number (asymptotic) scaling of streamwise turbulence intensity squared defined as ${I^2=\overline{u^2}/U^2}$, where $u$ and $U$ are the fluctuating and mean velocities, respectively…

Fluid Dynamics · Physics 2021-06-29 Nils T. Basse

The behavior of velocity fluctuations near a wall has long fascinated the turbulence community, because the prevalent theoretical framework of an attached-eddy hierarchy appears to predict infinite intensities as the Reynolds number tends…

Fluid Dynamics · Physics 2024-12-13 Javier Jiménez

Interactions between inertia-gravity waves and balanced flows lead to a spectral diffusion of wave action. Prior work has established that this diffusion is weak across constant frequency surfaces in three-dimensional settings, but can be…

Fluid Dynamics · Physics 2026-05-04 Nicholas DeFilippis , Oliver Bühler , K. Shafer Smith

Non-Newtonian fluids have a viscosity that varies with applied stress. Elastoviscoplastic fluids, the elastic, viscous and plastic properties of which are interconnected in a non-trivial way, belong to this category. We have performed…

Fluid Dynamics · Physics 2023-08-02 Mohamed S. Abdelgawad , Ianto Cannon , Marco E. Rosti

We study, by means of extensive direct numerical simulations, the turbulent flow produced by a two-dimensional cellular forcing in a cubic box with periodic boundary conditions. In spite of the strong anisotropy of the forcing, we find that…

Fluid Dynamics · Physics 2022-11-22 S. Berti , G. Boffetta , S. Musacchio