Large Eddy Simulation of Vortical Interactions in a Ducted Propulsor

Large-Eddy Simulation (LES) is performed to study the tip vortex flow in a ducted marine propulsor geometry with comparison to the experiments of Saraswat et al. (35^th Symp. Naval Hydro. 2024) and Michael et al. (35^th Symp. Naval Hydro. 2024). Near the design condition, such ducted propulsors produce multiple tip vortices whose mutual stretching is tied to cavitation inception. Understanding the pressure at which cavitation inception occurs is of engineering importance to avoid unwanted noise, vibration, and material erosion. In the present work, simulation results are compared to experimental cavitation observations and Particle Image Velocity (PIV) measurements. Differences between the instantaneous and time-averaged vortex orientations and interactions are presented. Likely cavitation inception locations predicted by the LES are examined through statistics of instantaneous low-pressure events below the minimum mean pressure. Results are presented for design and +10% off-design advance ratios.