A Robust 3D Particle Tracking Solver for In-flight Ice Accretion using Arbitrary Precision Arithmetic

A particle tracking code is presented to compute droplet trajectories within a known Eulerian flow field for in-flight ice accretion simulations. The implementation allows for hybrid or unstructured meshes used by common CFD solvers. A known vicinity algorithm was devised to identify particles inside the mesh by computing the intersection between the particle trajectory and the faces of the mesh elements. Arbitrary precision arithmetic is used in the intersection evaluation in order to avoid errors when selecting the exit face if the intersection point is close to or coincident with a vertex or an edge. State-of-the-art wall interaction models are used to take into account droplet rebound, splash and spread at the walls. Non planar surface elements are assumed to improve the accuracy in evaluating the trajectory of secondary re-emitted particles. The software exhibits almost linear scaling when running in parallel on a distributed memory system. The particle tracking code is assessed against the experimental results regarding the impingement of Supercooled Large Droplets over a wing.