Maneuverability characteristics of a fouling submarine near the seabed

Motion stability of a rough submarine within the vertical plane near the seabed is investigated in this study. The oblique towing tests, pure heave tests and pitch tests are numerically simulated based on a fully appended SUBOFF. Adaptive mesh refinement and overlapping mesh technologies are utilized. The numerical results are validated by comparing the simulated hydrodynamic coefficients with those provided by Defense Advanced Research Projects Agency. Effects of roughness height, roughness distribution, and seabed distance on hydrodynamic responses, hydrodynamic coefficients, and motion stability are analyzed. The findings reveal that both proximity to the seabed and hull roughness undermine the submarine motion stability. Specifically, as the rough submarine approaches the seabed, its motion stability decreases by 85.75%. Besides, the increasing roughness height results in a slower reduction in motion stability. Furthermore, the stern one-third hull fouling in infinite water depth leads to the most significant decrease in motion stability, with a reduction of 57.83% when roughness height is 489 μm. Conversely, the forward one-third and middle one-third hull fouling lead to reductions in motion stability by 17.04% and 10.00%, respectively. Thus, minimizing stern one-third hull fouling is identified as a beneficial measure for enhancing motion stability.