Hydrodynamic investigation of a remora-inspired autonomous underwater vehicle docking onto a benchmark submarine

To improve the cost-effectiveness and safety of offshore operations, autonomous underwater vehicles (AUVs) are widely used in various fields. However, traditional docking or recovery methods for AUV’s can be very inefficient as they require the mother vehicle to be stationary. Therefore, to reduce recovery operation cost, shorten the redeployment time and increase operational efficiency when compared to traditional docking methods, the development of underwater dynamic recovery systems for AUVs is critical. Recently the ‘hitchhiking’ behavior of remoras which have a symbiotic relationship with sharks has been investigated, and the numerical results showed that the boundary layers and adverse pressure gradient regions around the shark can provide a significant drag reduction on the remora when it attaches to the shark. To support the feasibility study of the underwater dynamic recovery system of AUVs, this paper develops a remora-like AUV and investigates the potential docking locations on a benchmark submarine, using the commercial computational fluid dynamics (CFD) software, STAR-CCM+. Self-propulsion simulations are conducted to identify the resistance performance of the AUV in different locations as affected by flow around the submarine. The boundary layer and the adverse pressure gradient are the two key elements that affected the AUV resistance. By researching the hydrodynamic characteristics, an optimal docking area is identified and presented to be further researched to fully enable this advanced dynamic docking operation.