2026 Volume 13 Issue 2 Pages 161-176
Although an autonomous mobile buoy to observe wave-height without a mooring rope has been developed, rotation of the front and rear propellers caused unintended turning during navigation. In this paper, the cause of this problem was investigated through computational fluid dynamics (CFD) analysis, and it was confirmed that the problem could be resolved by introducing a phase difference between the propellers. Conventional wave-height measurement systems, which are fixed to the seabed via mooring lines, suffer from limited coverage and high maintenance costs. Accordingly, a small autonomous mobile buoy has been developed. The buoy achieves forward propulsion through self-rotation using propellers mounted at the front and rear of a fully sealed cylindrical hull; however, unintended turning motion was observed. CFD analysis demonstrated that the interaction between the flows generated by the front- and rear-mounted propellers produces a yaw moment, causing the buoy to turn unintentionally. Furthermore, it was confirmed that the yaw moment can be reduced by introducing a phase difference between the propellers.
