Volumetric effects in viscous flows in circular and annular tubes with wavy walls

Fuente: arXiv
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Main Authors: Guo, Yisen, Thomas, John H.
Format: Preprint
Published: 2026
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author Guo, Yisen
Thomas, John H.
author_facet Guo, Yisen
Thomas, John H.
contents We point out that, in the usual way of specifying a sinusoidal waviness of the wall of a tube of circular cross section, in which the mean radius is kept constant, the interior volume of the tube increases with increasing wave amplitude. We compare this case with the case where the interior volume is kept constant by reducing the mean radius as the wave amplitude increases. We present and compare numerical results of these two cases for steady, pressure driven, laminar viscous flow in a tube with a stationary wavy wall, for both circular and annular tubes. The volume flow rate and the hydraulic resistance can differ in the two cases by as much as 10% for wave amplitudes as small as 20% of the mean radius and as much as 50% for larger wave amplitudes. For a circular tube, we derive a scaling law that relates the two cases based on dimensional analysis, allowing the behavior in the constant-volume case to be determined from that in the constant-mean-radius case. Additionally, we consider peristaltic pumping due to a moving sinusoidal wall wave and show that the volume-change effect is significant even at small wave amplitudes, and that the volume flow rates in the two cases can differ significantly, by as much as 50% as the wave amplitude approaches its maximum value.
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id arxiv_https___arxiv_org_abs_2603_04362
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Volumetric effects in viscous flows in circular and annular tubes with wavy walls
Guo, Yisen
Thomas, John H.
Fluid Dynamics
We point out that, in the usual way of specifying a sinusoidal waviness of the wall of a tube of circular cross section, in which the mean radius is kept constant, the interior volume of the tube increases with increasing wave amplitude. We compare this case with the case where the interior volume is kept constant by reducing the mean radius as the wave amplitude increases. We present and compare numerical results of these two cases for steady, pressure driven, laminar viscous flow in a tube with a stationary wavy wall, for both circular and annular tubes. The volume flow rate and the hydraulic resistance can differ in the two cases by as much as 10% for wave amplitudes as small as 20% of the mean radius and as much as 50% for larger wave amplitudes. For a circular tube, we derive a scaling law that relates the two cases based on dimensional analysis, allowing the behavior in the constant-volume case to be determined from that in the constant-mean-radius case. Additionally, we consider peristaltic pumping due to a moving sinusoidal wall wave and show that the volume-change effect is significant even at small wave amplitudes, and that the volume flow rates in the two cases can differ significantly, by as much as 50% as the wave amplitude approaches its maximum value.
title Volumetric effects in viscous flows in circular and annular tubes with wavy walls
topic Fluid Dynamics
url https://arxiv.org/abs/2603.04362