Research on the hydrodynamic performance of AUVs in small size open channel area

Abstract

When Autonomous Underwater Vehicles (AUVs) of different sizes sail in narrow water areas, their hydrodynamic performance is affected to varying degrees by boundaries. In this study, circulating water tank experiments and CFD simulations were conducted on three different-size ellipsoidal AUVs. The objective was to observe the influence of size on the hydrodynamics of AUVs moving at different speeds and different angles of attack in an open channel. Subsequently, a separate analysis was performed on the big size model under different sailing speeds to observe how the hydrodynamics are influenced by the boundaries of the open channel as the Froude number varies. Finally, a separate analysis was conducted to investigate the hydrodynamic effects of the open channel's free surface, bottom wall, and sidewalls on the model. It was found that the free surface has a bigger impact on an AUV's hydrodynamic performance than a solid wall. The findings show that the free surface has no effect on an AUV with a depth larger than 3.1D (AUV height D), and that hydrodynamic coefficients tend to be constant for W/B = 2.7 (channel width W, model width B) and higher.