This study considers the hydrodynamic characteristics of an AUV (autonomous underwater vehicle) near an uneven seabed. An improved hydrodynamic algorithm based on conformal mapping and the boundary element method (BEM) is proposed in this paper to improve the accuracy and efficiency of numerical computation. The proposed algorithm is validated by numerical examples. The effect of an uneven seabed on the pressure distribution of a hull surface is obtained. The improved algorithm is proven to be more efficient in the avoidance of seabed boundary interception and dispersion than conventional BEM.
The hydrodynamic performance of an AUV (autonomous underwater vehicle) plays an important role in AUV control and navigation and has received increasing interest by researchers in recent years (Abolvafaie et al., 2018; Kepler et al., 2018). The hydrodynamic model of an AUV should be accurate enough to meet the requirement of motion simulation and control design. At present, the motion control design of an AUV is normally based on the model in an unbounded water domain, which does not take the influence of the boundary of the water domain into consideration. There is significant demand for AUVs working near seabeds for military, scientific, and industrial purposes—for example, performing underwater search and rescue (Sahoo et al., 2019) and tracking oil spill and gas leakage (Kimura et al., 2013). There is a kind of AUV specially designed for seabed applications called an ocean bottom flying node (Qin et al., 2018). Similarly, AUV missions in polar areas for scientific goals have been widely reported (McPhail et al., 2019). Because of the complex flow around the AUV, the hydrodynamic characteristics of AUVs near a seabed (or ice shelf) have an obvious difference from those in unbound domains, which is an unfavorable factor for AUV stability, maneuvering control, and positioning accuracy, limiting the development of subsea docking and recovery technology.
