Effect of the geometric parameters on a flexible fiber motion in a tangentially injected divergent swirling tube flow

A particle-level simulation method is employed to study the effects of some geometric parameters, such as the injector diameter, the injection angle and position on fiber motions in a 3D compressible decaying swirling flow in a divergent tube. The flexibility of the fiber is defined by the bending and twisting displacements. The fiber-wall collision and compressible effects are considered here. The fiber with different complex configurations moves as spiral orbit with stream-wise direction. With the increase in the injector diameter, the deformation degree of the fiber increases. For a larger injector diameter, the fiber appears to be closed coil loops or asymmetric S-loopturn. The larger the injection angle is, the earlier the fiber starts to swirl and the larger the number of 'turn' is. The complex coiled configurations with entanglement can be observed under small injection angle. Especially, a 'zigzag' configuration is formed for larger injection angle and injection position.