Study of CFD prediction and surface roughness effect on AUV hull resistance performance

To optimize the resistance performance of autonomous underwater vehicle (AUV) hull, many previous scholars mainly studied the geometric shape and materials of AUV, but lacked the research on the surface roughness effect on the hull resistance. In this paper, take the Myring-shaped AUV hull for example, the computational domain distribution, grid independence verification and turbulence model are analyzed and discussed in detail. A computational fluid dynamics (CFD) calculation model is systematically established to predict the resistance performance of AUV hull. The simulation results are in good agreement with the theoretical data, which proves the reliability of the CFD model. Subsequently, the surface roughness effect on the hull drag is studied. First, taking the hull surface roughness height \({K}_{s}\) $K_s$ as 0.8 μm—100 μm, the friction resistance, pressure resistance and total resistance changes of the hull with the surface roughness height \({K}_{s}\) $K_s$ are studied when the advance speed is 1.5 m/s. It is found that the total resistance is the lowest when \({K}_{s}\) $K_s$ is 27.5 μm. Second, taking the surface roughness height as 0.8 μm, 12.5 μm, 50 μm, 75 μm and 100 μm, the change of the hull resistance with the advance speed is analyzed. It is found that the hull resistance increases with the increase of the speed. Third, when the speed is 1 m/s, 2 m/s and 2.5 m/s, respectively, the change of the hull resistance with the surface roughness height is analyzed. The results show that the corresponding optimal surface roughness heights are 39 μm, 21.5 μm and 17 μm, respectively. Finally, the surface roughness effect on the resistance performance of a torpedo-shaped hull is analyzed. It is found that its optimal surface roughness height is very close to that of the Myring-shaped hull.