Streak generation in viscosity-stratified wall-bounded flows
Fluid Dynamics
2025-08-29 v1
Abstract
Streamwise elongated flow structures, or streaks, dominate wall-bounded flows. We show that the renowned lift-up mechanism, that generates streaks, is significantly altered by viscosity stratification. We additionally identify a novel pathway for streak generation: the viscosity-stratified lift-up mechanism. The competition and cooperation of the streaks generated by these mechanisms provides an explanation for trends in viscosity-stratified Poiseuille flows, and remarkably, the opposing trends in Couette flows as well. Our theoretical observations are substantiated by numerical experiments.
Keywords
Cite
@article{arxiv.2508.20636,
title = {Streak generation in viscosity-stratified wall-bounded flows},
author = {Anagha Madhusudanan and Simon J. Illingworth and Rama Govindarajan},
journal= {arXiv preprint arXiv:2508.20636},
year = {2025}
}