Vortex reconnection and turbulence cascade

J Yao, F Hussain - Annual Review of Fluid Mechanics, 2022 - annualreviews.org
As a fundamental topology-transforming event, reconnection plays a significant role in the
dynamics of plasmas, polymers, DNA, and fluids—both (classical) viscous and quantum …

Role of internal structures within a vortex in helicity dynamics

W Shen, J Yao, F Hussain, Y Yang - Journal of Fluid Mechanics, 2023 - cambridge.org
Helicity, an invariant under ideal-fluid (Euler) evolution, has a topological interpretation in
terms of writhe and twist for a closed vortex tube, but accurately quantifying twist is …

Lagrangian dynamics and regularity of the spin Euler equation

Z Meng, Y Yang - Journal of Fluid Mechanics, 2024 - cambridge.org
We derive the spin Euler equation for ideal flows by applying the spherical Clebsch
mapping. This equation is based on the spin vector, a unit vector field encoding vortex lines …

Topological transition and helicity conversion of vortex knots and links

W Shen, J Yao, F Hussain, Y Yang - Journal of Fluid Mechanics, 2022 - cambridge.org
Topological transition and helicity conversion of vortex torus knots and links are studied
using direct numerical simulations of the incompressible Navier–Stokes equations. We find …

Helicity dynamics in viscous vortex links

J Yao, W Shen, Y Yang, F Hussain - Journal of Fluid Mechanics, 2022 - cambridge.org
The dynamics of two slender Hopf-linked vortex rings at vortex Reynolds numbers ($
Re\equiv\varGamma/\nu,\mathrm {circulation/viscosity} $) $2000 $, $3000 $ and $4000 $ is …

Evolution of dissipative fluid flows with imposed helicity conservation

Z Meng, W Shen, Y Yang - Journal of Fluid Mechanics, 2023 - cambridge.org
We propose the helicity-conserved Navier–Stokes (HCNS) equation by modifying the non-
ideal force term in the Navier–Stokes (NS) equation. The corresponding HCNS flow has …

Creation of quantum knots and links driven by minimal surfaces

S Zuccher, RL Ricca - Journal of Fluid Mechanics, 2022 - cambridge.org
Using an improved numerical code we investigate the creation and evolution of quantum
knots and links as defects of the Gross–Pitaevskii equation. The particular constraints put on …

Velocity gradient analysis of a head-on vortex ring collision

R Arun, T Colonius - Journal of Fluid Mechanics, 2024 - cambridge.org
We simulate the head-on collision between vortex rings with circulation Reynolds numbers
of 4000 using an adaptive, multiresolution solver based on the lattice Green's function. The …

Parallel algorithm for particle-grid dual discretization

LY Zhao, S Wang, Y Liu - Computational Mechanics, 2023 - Springer
Particle-grid dual discretization methods employ one group of Lagrangian particles and one
set of background grid, which demonstrate attractive properties because they inherit both the …

Polarized vortex reconnection

J Yao, F Hussain - Journal of Fluid Mechanics, 2021 - cambridge.org
Polarized vortical structures (ie with axial flow, thus coiled vortex lines) are generic to
turbulent flows–hence the importance of their dynamics, interactions and cascade. Direct …