Numerical Investigation on Interactive Hydrodynamic Performance of Two Adjacent Unmanned Underwater Vehicles (UUVs)

This study investigates the effectiveness of UUV formations during navigation to designated target areas. The research focuses on propeller-equipped UUVs and employs a computational fluid dynamics (CFD) methodology to analyze the hydrodynamic interactions among multiple UUV formations while en route to their targeted exploration areas. Utilizing the relative drag coefficients (rl and rf) and static thrust (Rfleets) as analytical parameters, this paper defines the relative distances (a and b) between UUVs within a formation and conducts a comparative analysis of the hydrodynamic performance between individual UUVs and formation configurations. The study establishes correlations between relative distances and the hydrodynamic performance of formations. The findings reveal the following: 1. For both the lead UUV and the following UUV within the formation, the rl and rf heatmaps exhibit two distinct regions: a thrust region and a drag region. Notably, these regions significantly overlap. The maximum rl is 31.23%, while the minimum rf is -20.9%, corresponding to relative distances of a = 0.12 and b = 1.5. Conversely, the minimum rl is -12.2%, while the maximum rf is 22.03%, with relative distances of a = 1.1 and b = 0.2; 2. An analysis of formation static thrust Rfleets reveals that it can be up to 7% greater than the drag experienced by self-propelled UUVs when relative distances a and b are set to 1.1 and 1, respectively. This highlights the enhanced performance achievable through formation navigation. The results presented in this paper offer valuable theoretical insights into the optimal design of relative distances within UUV formations, contributing to the advancement of UUV formation navigation strategies.