Study on analysis and simulation of hydrodynamic characteristics of autonomous underwater helicopter

An autonomous underwater helicopter (AUH) is an autonomous underwater vehicle that is highly useful for performing subsea missions. It was proposed at the Ocean College of Zhejiang University. An appropriate hull structure for an AUH needs to be adjusted to perform multidirectional movement, rotation, and precise hovering in the marine environment. The viable geometric form of the AUH also needs to be simple for easy manufacturing, such as spherical, ellipsoidal, or disk shapes, which could be considered feasible designs for the AUH. The disk-shaped AUH has lower drag in the horizontal plane than other shapes but higher drag in the vertical plane compared to other profiles. However, the disk shape allows the AUH to maintain good position holding and stability in vertical plane movements. The physical model and boundary conditions are built according to the experimental model of the previous research. The continuity, Navier-Stokes, and energy equations are solved by the finite volume method. In this study, the hydrodynamic characteristics of an AUH are analyzed and simulated by ANSYS Fluent software. The numerical results clearly show the velocity field and pressure distribution around the AUH when it moves through the water. The larger the velocity and angle of attack, the larger the drag force. The numerical results of the hydrodynamic characteristics of the AUH contribute to increasing the efficiency, maneuverability, and energy savings when an AUH moves through the ocean. This is the basis for achieving the optimal design of disk-shaped autonomous underwater vehicles in the future.