Experimental study of a three dimensional cylinder-filament system

TL;DR

This experimental study investigates how a filament attached behind a three-dimensional cylinder behaves depending on its length, revealing different alignment patterns and underlying instability mechanisms.

Contribution

It provides new experimental insights into the behavior and bifurcations of a filament in the wake of a 3D cylinder, highlighting length-dependent alignment patterns.

Findings

Long and short filaments align with incoming flow.

Intermediate filaments lie on the cylinder and align with its axis.

Bifurcations are related to buckling and inverted-pendulum-like instabilities.

Abstract

This experimental study reports on the behavior of a filament attached to the rear of a three- dimensional cylinder. The axis of the cylinder is placed normal to a uniform incoming flow and the filament is free to move in the cylinder wake. The mean position of the filament is studied as a function of the filament length L. It is found that for long (L/D > 6.5, where D is the cylinder diameter) and short (L/D < 2) filaments the mean position of the filament tends to align with the incoming flow, whereas for intermediate filament lengths (2 < L/D < 6.5) the filament lies down on the cylinder and tends to align with the cylinder axis. The underlying mechanism of the bifurcations are discussed and related to buckling and inverted-pendulum-like instabilities.