Theory of swimming filaments in viscoelastic media

TL;DR

This paper investigates how viscoelastic properties of fluids affect the swimming behavior of filaments, such as sperm, revealing that viscoelasticity generally reduces speed and can even reverse swimming direction.

Contribution

It provides a theoretical analysis of filament swimming in nonlinear viscoelastic fluids using the Upper Convected Maxwell model, including velocity and force calculations for infinite cylinders.

Findings

Viscoelasticity tends to decrease swimming speed.

Changes in beating patterns can reverse swimming direction.

Theoretical framework for filament swimming in viscoelastic media.

Abstract

Motivated by the swimming of sperm in the non-Newtonian fluids of the female mammalian reproductive tract, we examine the swimming of filaments in the nonlinear viscoelastic Upper Convected Maxwell model. We obtain the swimming velocity and hydrodynamic force exerted on an infinitely long cylinder with prescribed beating pattern. We use these results to examine the swimming of a simplified sliding-filament model for a sperm flagellum. Viscoelasticity tends to decrease swimming speed, and changes in the beating patterns due to viscoelasticity can reverse swimming direction.