Numerical analysis of second-order wave forces acting on an autonomous underwater helicopter using panel method

In this study, the hydrodynamic performance of a dish-shaped autonomous underwater helicopter (AUH) in waves near the sea surface is examined. The AUH is a novel type of autonomous underwater vehicle (AUV) that has excellent maneuverability and flexibility. The hydrodynamic performance of a dish-shaped autonomous underwater helicopter (AUH) in waves near the sea surface is estimated. An AUH is a novel type of autonomous underwater vehicle (AUV) that possesses excellent maneuverability and flexibility. The employed ANSYS-AQWA, which is well-known hydrodynamic analysis software based on potential fluid theory, is adopted to compute the effects of waves on the AUH in both the frequency domain and the time domain. The validity and accuracy of the proposed approach are verified through a comparison of results of a spheroid-model case with relevant literature results. First-order wave forces and moments in six degrees of freedom are analyzed at different wave frequencies and submergence depths. Furthermore, the second-order mean wave forces and moments in the heave and pitch directions are determined. The analyses reveal that the wave forces are significant when the AUH operates near the sea surface. Numerical results in the time domain are then acquired under different wave conditions. The proposed approach conveniently and accurately predicts the hydrodynamic characteristics of submerged bodies operating in sea waves.