The maneuverability and hydrodynamics of a tethered underwater vehicle based on adaptive mesh refinement

Abstract

The paper attempts to supplement the current research on the trajectory tracking of the tethered underwater vehicle at the different towing speeds, which only focuses on the optimization and innovation of the control method itself, while ignoring the research shortcomings of various hydrodynamic factors. The hydrodynamic model is consist of the umbilical cable, Ka 4–70/19A ducted propellers, and hydrofoils. The finite segment method is used to study the umbilical cable, which utilizes the multiple cylinders connected by the ball joint. The rotation of the hydrofoils and ducted propellers is simulated by the sliding mesh, the movement of the tethered underwater vehicle with multiple control equipment is solved by the interpolation of overset grid. The numerical simulation is carried out in the numerical tank governed by the Navier-Stokes equation solved by Star-ccm+ (a commercial software based on the finite volume method). The trajectory and hydrodynamic performance of the tethered underwater vehicle change significantly when the towing speed changes from low speed to high speed. The coupling effect of the control equipment, the umbilical cable and the underwater vehicle is so important that it determines the hydrodynamic performance characteristic of the tethered underwater vehicle. The ducted propellers and hydrofoils are a mutually complementary relationship for the trajectory control of the tethered underwater vehicle. In the floating stage, the control effect of the ducted propeller is better than the hydrofoil. In the depth keeping stage, the control effect of the hydrofoil is better than the ducted propeller, especially in the condition of high towing speed. The hydrodynamic performance of the umbilical cable is so significant for the motion that it cannot be ignored.