Analysis of drag property on lode appendage of multi-load AUV

After the separation of multi-load AUV, AUV becomes into two parts: load and carrier. Separation destroyed the original shape with good hydrodynamic characteristics of AUV. How to reduce the drag of load has great significance on the separation of multi-load AUV. In order to study the influence of appendage of multi-load AUV on friction, the numerical calculations on original and modified models with different kinds of appendages are carried out based on the SST k-ω turbulence model. The results show that the appendage can avoid the phenomenon of fluid premature separation, so as to reduce the intensity and scale of the wake vortex, and achieves drag reduction effect by reducing pressure friction. Conclusions are drawn as: (1) Cylindrical appendage should have a suitable diameter and length to be matched, in order to achieve the best drag reduction effect; (2) The drag reduction effect of hemispherical appendage is good, but the drag reduction effect is not enhanced with increasing diameter within a certain range; (3) Drag reduction effect of the combination appendage is better than the simple cylindrical and hemispherical appendage, and the amount of drag reduction can reach 50%.