A Novel Method for Dynamic Simulation of Flexible Fibers in a 3D Swirling Flow

Abstract

A novel method is proposed for simulating the motion of flexible fibers in a 3D swirling flow, where the fiber is modeled as a chain of beads connected through mass-less rods. The bending and twisting displacements of the successive beads are used to represent the deformation of the fiber. In addition, the drag and shear-induced lift forces are considered in the proposed model as parts of external loads acting on the fiber in the swirling flow. In the numerical simulation, the spiral motion trajectory of the fiber is observed to have a springy or helical configuration. The numerical results are validated by experimental visualization using high-speed photography.

Study on the dynamics of chitosan/cotton fiber in an airflow around two rotating cylinders

“…Therefore, we will extend the bead–rod fiber model of Guo and Xu by considering the stretching force of the fiber in this study. 11,12 The fiber is composed of n beads of radius r , which are connected by n – 1 mass-less rods. Only beads are affected by the stretching, bending, and twisting restoring forces, as well as the hydro forces from the fluid, and the rods only serve to transmit forces and maintain the configuration of the fiber.…”

“…To overcome such restrictions, Schmid and colleagues modeled flexible fibers as chains of circular cylinders with hemispherical end-caps connected by ball-and-socket joints. 9 Based on small deflection theory, 10 we have introduced a bead–rod-chain fiber model, 11,12 in which the rods only serve to transmit forces and maintain the configuration of the fiber, to calculate the motion of the flexible fiber in a swirling flow. This model can also save computational time because fewer beads are used.…”

Simulating the motion of a flexible fiber in 3D tangentially injected swirling airflow in a straight pipe—Effects of some parameters

“…The bead-rod fiber model [19,20] and the computational method [20] used in this work were described in detail, and validated [19,20] for the case of isolated fiber by Guo and Xu. Here, only the most important aspects of the theoretical framework are outlined.…”

“…It also should note that the longer the 'coarse-grained' particle length, the larger the error of the simulation as compared to the bead chain model [18]. In addition, a bead-rod chain, in which the rods only serve to transmit forces and maintain the configuration of the fiber, was proposed to simulate the motion of the flexible fiber in a swirling flow [19,20]. This model can also save computational time because of fewer beads adopted.…”

“…In this study, the fiber suspension model of Guo and Xu [19,20] is employed to simulate the dynamics of a flexible fiber in the three-dimensional turbulent swirling flow induced by tangential inlets in a straight tube. A brief outline of the model is provided in Section 2, in which the one-way coupling Euler-Lagrange approach is utilized.…”