Computational Fluid Dynamics Study of Magnus Force on an Axis-Symmetric, Disk-Type AUV with Symmetric Propulsion

Abstract

In this paper, the Magnus force induced by a disk-type, spinnable autonomous underwater vehicle (AUV), i.e., autonomous underwater helicopter (AUH), was predicted to promote the spinning AUH moving away from a deep-sea region with temporary and shockable ocean current. The simulation technique of the ANSYS-CFX solver based on viscous computational fluid dynamics (CFD) was employed to analyze the hydrodynamic performance of the spinning AUH and its high-speed propellers in uniform flow conditions. The behavior of the spinning AUH in currents can obviously alter the pressure distribution on both sides of the disk-shaped hull form, resulting in a differential pressure force in the horizontal plane, i.e., Magnus force. The simulation results show that this induced force can enable an AUH at 1 knot service speed to successfully move away from a sudden, transient, and/or steady, uniform ocean current region with inflow velocities of 1–2 knots in deep-sea conditions. The Magnus force induced by symmetrically configurated propeller couple force can be more efficient and effective at driving the AUH’s escape from the current spoiler zone than driving the AUH using the two high-revolution propellers directly. A suitable mechanical power energy-saving matching point integrating the AUH and symmetric propulsion was determined to compare the proposed method and two conventional methods for AUH escape from currents. The comparison results prove that the proposed method is effective and efficient. This study provides a significant reference for the interdependent relationship between the effective spinning speed of an AUH, subject to couple force, controlled propeller revolution, AUH speed, and battery capacity, and the range of ocean currents.