Unconfined flow of a non-Newtonian power-law fluid past counter-rotating circular cylinders

Fuente: arXiv
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Main Authors: Malviya, Lekhraj, Bharti, Ram Prakash, Lal, Abhishek Kumar
Format: Preprint
Published: 2025
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author Malviya, Lekhraj
Bharti, Ram Prakash
Lal, Abhishek Kumar
author_facet Malviya, Lekhraj
Bharti, Ram Prakash
Lal, Abhishek Kumar
contents This study numerically examines the steady unconfined laminar flow of incompressible non-Newtonian power-law fluids past a pair of side-by-side counter-rotating circular cylinders using the finite element method. The cylinders simultaneously rotate at equal angular speeds in opposite directions, with the upper cylinder (UC) rotating clockwise and the lower cylinder (LC) counterclockwise. The numerical simulations are performed over wide parameter ranges: power-law index ($0.2 \le n \le 1.8$), rotational rate ($0 \le α\le 2$), gap ratio ($0.2 \le G \le 1$), and Reynolds number ($1 \le Re \le 40$). The detailed influence of these flow parameters on key flow characteristics, including streamlines, surface pressure, centerline velocity, and individual as well as total drag and lift coefficients, is systematically analyzed. For stationary cylinders ($α= 0$), a twin-vortex structure forms in the wake, which progressively vanishes with increasing rotation ($α= 2$). The surface pressure coefficient attains its maximum values for shear-thickening fluids ($n > 1$) at higher rotational speeds, irrespective of the gap ratio. The total drag coefficient ($C_D$) decreases with increasing $α$ and $n$, whereas the lift coefficient ($C_L$) exhibits a more intricate dependence on the flow parameters. The results provide fundamental insights into the interplay between rotation, non-Newtonian rheology, and geometric confinement in determining the hydrodynamic behavior of rotating cylinder systems.
format Preprint
id arxiv_https___arxiv_org_abs_2511_12954
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unconfined flow of a non-Newtonian power-law fluid past counter-rotating circular cylinders
Malviya, Lekhraj
Bharti, Ram Prakash
Lal, Abhishek Kumar
Fluid Dynamics
This study numerically examines the steady unconfined laminar flow of incompressible non-Newtonian power-law fluids past a pair of side-by-side counter-rotating circular cylinders using the finite element method. The cylinders simultaneously rotate at equal angular speeds in opposite directions, with the upper cylinder (UC) rotating clockwise and the lower cylinder (LC) counterclockwise. The numerical simulations are performed over wide parameter ranges: power-law index ($0.2 \le n \le 1.8$), rotational rate ($0 \le α\le 2$), gap ratio ($0.2 \le G \le 1$), and Reynolds number ($1 \le Re \le 40$). The detailed influence of these flow parameters on key flow characteristics, including streamlines, surface pressure, centerline velocity, and individual as well as total drag and lift coefficients, is systematically analyzed. For stationary cylinders ($α= 0$), a twin-vortex structure forms in the wake, which progressively vanishes with increasing rotation ($α= 2$). The surface pressure coefficient attains its maximum values for shear-thickening fluids ($n > 1$) at higher rotational speeds, irrespective of the gap ratio. The total drag coefficient ($C_D$) decreases with increasing $α$ and $n$, whereas the lift coefficient ($C_L$) exhibits a more intricate dependence on the flow parameters. The results provide fundamental insights into the interplay between rotation, non-Newtonian rheology, and geometric confinement in determining the hydrodynamic behavior of rotating cylinder systems.
title Unconfined flow of a non-Newtonian power-law fluid past counter-rotating circular cylinders
topic Fluid Dynamics
url https://arxiv.org/abs/2511.12954