Multiscale velocity gradients in turbulence

PL Johnson, M Wilczek - Annual Review of Fluid Mechanics, 2024‏ - annualreviews.org
Understanding and predicting turbulent flow phenomena remain a challenge for both theory
and applications. The nonlinear and nonlocal character of small-scale turbulence can be …

Energy transfer from large to small scales in turbulence by multiscale nonlinear strain and vorticity interactions

PL Johnson - Physical review letters, 2020‏ - APS
An intrinsic feature of turbulent flows is an enhanced rate of mixing and kinetic energy
dissipation due to the rapid generation of small-scale motions from large-scale excitation …

Hierarchy of coherent vortices in turbulence behind a cylinder

J Fu**o, Y Motoori, S Goto - Journal of Fluid Mechanics, 2023‏ - cambridge.org
To draw concrete pictures of the hierarchy of multiscale coherent vortices in turbulence
behind a cylinder and to reveal their sustaining mechanism, we conduct direct numerical …

On the role of vorticity stretching and strain self-amplification in the turbulence energy cascade

PL Johnson - Journal of Fluid Mechanics, 2021‏ - cambridge.org
The tendency of turbulent flows to produce fine-scale motions from large-scale energy
injection is often viewed as a scale-wise cascade of kinetic energy driven by vorticity …

Direct numerical simulation of particle-laden flow in an open channel at

W Gao, R Samtaney, DH Richter - Journal of Fluid Mechanics, 2023‏ - cambridge.org
We perform two-way coupled direct numerical simulation of particle-laden flow in an open
channel at a friction Reynolds number (). The spatial structures are investigated with …

Generation mechanism of a hierarchy of vortices in a turbulent boundary layer

Y Motoori, S Goto - Journal of Fluid Mechanics, 2019‏ - cambridge.org
To understand the generation mechanism of a hierarchy of multiscale vortices in a high-
Reynolds-number turbulent boundary layer, we conduct direct numerical simulations and …

Alignment of inertialess spheroidal particles in flow-structure-dominated regions of turbulent channel flow: shape effect

Z Cui, L Zhao - Acta Mechanica Sinica, 2024‏ - Springer
The alignment of elongated fibers and thin disks is known to be significantly influenced by
the presence of fluid coherent structures in near-wall turbulence (Cui et al. 2021). However …

On the role of turbulent large-scale streaks in generating sediment ridges

M Scherer, M Uhlmann, AG Kidanemariam… - Journal of Fluid …, 2022‏ - cambridge.org
The role of turbulent large-scale streaks or large-scale motions in forming subaqueous
sediment ridges on an initially flat sediment bed is investigated with the aid of particle …

Role of the hierarchy of coherent structures in the transport of heavy small particles in turbulent channel flow

Y Motoori, CK Wong, S Goto - Journal of Fluid Mechanics, 2022‏ - cambridge.org
To investigate the transport of heavy small particles (inertial particles) in high-Reynolds-
number wall turbulence, we conduct direct numerical simulations of inertial particles in …

Hierarchy of coherent structures and real-space energy transfer in turbulent channel flow

Y Motoori, S Goto - Journal of Fluid Mechanics, 2021‏ - cambridge.org
By analysing a database (Lozano-Durán & Jiménez, Phys. Fluids, vol. 26, 2014, 011702) of
fully developed turbulent channel flow at the friction Reynolds number, we investigate the …