Linear and nonlinear instabilities in highly shear thinning fluid flow through a pipe
Abstract
Shear-thinning fluids flowing through pipes are crucial in many practical applications, yet many unresolved problems remain regarding their turbulent transition. Using highly robust numerical tools for the Carreau-Yasuda model, we discovered that linear instability can arise when the power-law index falls below 0.35. This inelastic non-axisymmetric instability can universally arise in generalised Newtonian fluids that extend the power-law model. The viscosity ratio from infinite to zero shear rate can significantly impact instability, even if it is small. Two branches of finite-amplitude travelling wave solutions bifurcate subcritically from the linear critical point. The solutions exhibit sublaminar drag reduction, a phenomenon not possible in the Newtonian case.
Cite
@article{arxiv.2412.10037,
title = {Linear and nonlinear instabilities in highly shear thinning fluid flow through a pipe},
author = {Xuerao He and Kengo Deguchi and Runjie Song and Hugh M. Blackburn},
journal= {arXiv preprint arXiv:2412.10037},
year = {2025}
}
Comments
24 pages, 10 figures