Maneuvering Stability Analysis of a Fouling Autonomous Underwater Vehicle in Horizontal Plane

During the operation of a submerged submarine, its surface will inevitably suffer from fouling, which will affect its hydrodynamic performance. In this paper, the horizontal maneuvering stability of the rough submerged submarine is studied based on the RANS method, where the Defense Advanced Research Projects Agency (DARPA) SUBOFF model developed by the David Taylor Research Centre (DTRC) is taken as the object hull. An appropriate roughness function model proposed by Demirel et al. (2017) for a range of representative coating and fouling conditions is selected to describe the roughness conditions. The hydrodynamics of the smooth SUBOFF model in infinite depth and wide area are calculated, and the validity of the numerical results is verified by the results of the tank test. The hydrodynamic coefficients of translation and rotation of the rough SUBOFF are obtained through the oblique towing tests and the pure yaw tests. According to Routh’s stability criterion, the horizontal maneuvering stability index of rough SUBOFF is obtained. Subsequently, the impact of the roughness height and the distribution position on the horizontal maneuvering stability is analyzed. The results show that when the surface of the submarine is partially covered with deteriorated coating or light slime, the stability index in the horizontal plane decreases by 31.70% for the case of stern one-third of the area fouled only, which is more hazardous than the case of forward one-third of area fouled only (6.23% decrease) or the case of middle one-third of the area fouled only (4.02% decrease). Therefore, minimizing the roughness attached to the stern surface is very beneficial in maintaining the stability of submarines.