A scheme for rigid bodies within highly viscous liquids

We present a Smoothed Particle Hydrodynamics (SPH) scheme suitable to model rigid bodies suspended within highly viscous fluids. This scheme is motivated by a slurrybased Additive Manufacturing (AM) process, which will be studied using SPH. During the process, grains suspended in a highly viscous paste are being printed through a process nozzle. Microscopic simulations in which those rigid bodies are resolved in high detail give insight into complex orientation dynamics due to grain-grain-interactions and viscous shear forces. The modelling challenge is composed on one hand of the extremely high viscosity and on the other hand of the rigid body dynamics. In the SPH literature, methods exist to either handle highly viscous fluids or to handle suspended rigid bodies; a combination of both methods, however, has not been reported yet. In the present paper, we provide detailed algorithms for both, the viscosity solver and the rigid body solver, and we further show how both solvers can be combined with ease. Demonstration cases for the successful application of our method are discussed.