Experimental study of a three-dimensional cylinder–filament system

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 is discussed and related to buckling and inverted-pendulum-like instabilities.