Radial migration and motion characteristics of elastic fibers in cylindrical Couette flow: a numerical simulation study

This study investigated the motion characteristics of an elastic fiber migrating in cylindrical Couette flow through numerical simulation. The immersed boundary-lattice Boltzmann method was employed to solve for fluid–fiber interaction. The results demonstrate a clear and noteworthy trend of radial migration in fiber movement as a result of centrifugal force. During radial migration, the elastic fiber first undergoes a non-recurring tumbling motion, then switches to a translation motion, and arrives at the outer cylinder with a slightly curved morphology. Increasing the Reynolds number (Re) and Dean number of the flow field enhances both fiber migration efficiency and the degree of fiber deformation. An increase in Re slows down the radial migration of the fiber during the tumbling stage, while accelerating the radial migration during the translation stage. When shorter fibers are initially placed close to the outer cylinder, the wall’s influence may delay or even prevent their tumbling motion. Extending the fiber length can markedly encourage tumbling motion in such cases. As tumbling motions speed up the migration process, increasing the length of the fiber leads to increased radial migration efficiency.