SPH-DEM modeling of cable-controlled ROVs: Underwater mobility and path planning

Abstract

Remotely operated vehicles (ROVs) are commonly used in water conservation initiatives to inspect underwater structures. However, significant issues remain in guaranteeing the safety of ROVs during field testing, such as loss of control in complex flow regimes and cable breakage. An SPH-DEM numerical model is constructed in this paper to characterize the motion properties of cable-controlled ROVs in complex flow scenarios such as flood discharge, gate leakage, and wave impact. Two dam underwater detection tests are carried out to reveal the damage mode or loss of the cable-controlled ROV. Furthermore, simulations of two benchmark scenarios are used to validate the SPH-DEM coupling model. In the water entry test for a sphere, our simulated depth has a maximum relative error of 12.38% compared to the experimental value, and a maximum relative error of 7.52% compared to the theoretical value. Following that, the interaction mechanism between the submersible vehicle, current, cable, and hydraulic structure is investigated. The findings highlight the importance of flow velocity near the underwater gate and cable length in impacting the precise attitude control of cable-controlled ROVs. Furthermore, it is clear that most occurrences of cable-controlled ROV damage or loss result from the ROV becoming entrapped or from cable breakage. This numerical investigation provides critical insights into guaranteeing the safe operation of cable-controlled ROVs in real-world detection situations.