Motivation, Development and Verification of a Rapid 3D Lagrangian Impingement Code - Trajectory and Catch 3D+ (TAC3D+)

This paper details the motivation, development and validation of a rapid 3D Lagrangian impingement code, Trajectory and Catch 3D+ (TAC3D+). AeroTex’s motivation to develop a 3D Lagrangian method was primarily driven by the inherent mesh dependent dissipation effect found in their 3D Eulerian Water Catch code (EWC) [1]. Studies performed by AeroTex have shown that for geometries where there are aft impingement regions that are partly shadowed by a more forward impingement region, the level of water flux dissipation can be significant, particularly if the mesh is coarse and the impingement region is far aft. Examples of issues where this may be a particular issue would be impingement on a centerline aft mounted engine or the calculation of impingement on the wing root/belly fairing. The code has been developed around a modified version of the OpenFOAM Lagrangian solver. The analysis process consists of three main phases; a coarse droplet trajectory calculation to identify the region of interest, a refined trajectory calculation that is sufficiently fine to calculate local water collection and a surface water collection efficiency calculation including mass loss due to splash and bounce associated with large droplets where applicable. The code allows the user to utilize multiple cluster queues to spread the job across multiple compute nodes to deliver the solution rapidly. The TAC3D+ code has been verified against a selection of 2D and 3D cases including some incorporating splash and bounce effects. The code is undergoing further development to incorporate the physics associated with ice crystals and the re-impingement of splashed particles. In addition, AeroTex are exploring methods to make the code even more efficient by maximizing time steps, utilizing different integration schemes and potential for the use of GPUs.