Numerical Estimation of Hydrodynamic Derivatives of a Biomimetic Autonomous Underwater Vehicle by Captive Model Tests

Autonomous Underwater Vehicles are used to perform underwater inspection, survey, and surveillance tasks and biomimetic AUVs are finding wide applications due to their inherent advantages like a stealth operation, power efficiency, etc. Since AUVs run on batteries, they should be well-maneuvrable and controllable for the desired operation, and provide longer endurance. So, the accurate prediction of the hydrodynamic coefficients of an AUV is crucial throughout the design phase. In the present study, a suitable 6 DOF mathematical model is selected and the captive model tests are performed in the numerical environment for the designed bio-inspired AUV. The steady and unsteady simulations are carried out in horizontal and vertical planes to arrive at the trajectories of forces and moments. The hydrodynamic derivatives are then obtained by solving these trajectories using the Fourier analysis. Finally, the vehicle’s straight-line stability is assessed in horizontal and vertical planes.