Multiphase simulation of fiber suspension flows using immersed boundary methods

Fiber suspension simulations are challenging since they involve transient fluid flow with immersed solid objects subject to large displacements and rotations. In the present work, a beam model in co-rotational formulation is coupled with a fluid solver using immersed boundary methods. The model is used to simulate a fiber in a shear flow and excellent agreement is found with Jeffery's equations. The shapes of fibers deforming in a shear flow are found to be in qualitative agreement with shapes observed in experiments. The flow of a fiber suspension is studied by simulating early paper forming with one-way and semi-two-way coupling. It is found that the flow through the fiber web needs to be resolved in order to predict the retention of fibers in the fiber web.