Transport and deposition of flexible fibers in turbulent duct flows

Transport, dispersion, and deposition of flexible fibrous particles in the near-wall coherent vortices in a turbulent duct flow are studied. The vortical flow field is modeled as a sequence of plane stagnation point flows. Fibers are assumed to be inextensible but completely flexible. That is, fibers have no stiffness and offer no resistance to bending. In the simulation, a flexible fiber is divided into many segments. Interactions of each element with the adjacent elements are through interfacial forces that are evaluated as part of the solution. For different fiber diameters, aspect ratios, and initial configurations, deposition velocities are evaluated, and the fiber dispersion is analyzed. An empirical equation for the deposition velocity of flexible fibers is also developed. The results for flexible fiber deposition rate are compared with those for rigid straight fibers and the empirical equation predictions. Copyright © 2001 Elsevier Science B.V.