Flexible fiber motion in the flow field of a cylinder

In the forming section of a papermachine, a water suspension of pulp fibers is drained through a forming fabric. One canonical test case that incorporates some key features of this process is that which studies the interaction of a single fiber with a cylinder. This article concerns numerical simulations of this interaction. he seemingly simple flow of a fiber near a cylinder involves consideration of a number of variables including: the fiber length, diameter, and stiffness; the fluid velocity, density and viscosity; the fiber initial orientation and position; and the frictional properties of the fiber/cylinder interface. There is a range of dimensionless groups for which the fiber can hang up on the cylinder, whereas for other values of the dimensionless groups the fiber slides off the cylinder. These results provide fundamental insight into the linting process in papermaking, and suggest potential conditions which may encourage linting in a papermachine. The results may also be useful in understanding other physical phenomena, such as vegetation entanglement in storm drains, hair clogging in sink stoppers and inhalation of fibers in the respiratory tract.