Research on Hydrodynamic Characteristics and Gliding Performance of Underwater Glider “HaiXun 4000”

Compared with common underwater glider, the 4 000-meter underwater glider needs larger volume adjustment of its buoyancy control system in order to overcome the influence of seawater density change. Accurate dynamic model and hydrodynamic coefficient are the basis for realizing its control system design and accurate navigation. On the premise that its structural parameters are determined and the dynamic model is known, this paper aims to obtain accurate hydrodynamic coefficient and predict its performance, so as to provide control variables and optimization directions for the control system. Taking the 4 000-meter underwater glider “HaiXun 4000” as the research object, theoretical calculation, CFD simulation and experimental data analysis are combined to analyze the influence of the horizontal wing parameters on the gliding performance of the underwater glider, hence the hydrodynamic coefficient of constant motion in longitudinal plane is obtained, and the performance of the glider is predicted. Through the analysis of test data, the gliding speeds corresponding to different net buoyancy under typical gliding conditions are obtained and compared with the theoretical calculation to verify the correctness of the theoretical calculation. The results show that the error between actual pitch angle control and theoretical calculation is less than 5%, and the error between gliding speed and theoretical calculation under the actual net buoyancy of the test is within 15%, meeting the error requirements of 20% of the corresponding control amount for the control system. This research may provide a reference for further optimization and improvement of the control system.