Numerical Study on the Interaction between Ocean Current Power Generator and Unmanned Underwater Vehicle

The unmanned underwater vehicle (UUV) can effectively utilize marine renewable energy after equipping the UUV with an accompanying power generator that improve its long-range endurance. In order to study the interaction between the UUV and the ocean current power generator, a coupled hydrodynamic model of the counter-rotating type turbine and the UUV hull was established. Based on the RANS model and the sliding grid method, this paper analyzed the influence of the ocean current power generator on the straight-ahead resistance and hydrodynamic coefficient of the UUV in the non-working state, and calculated the UUV yaw moment and its surrounding flow field characteristics with the power generator in the working state. Then, the effect of the drift angle on the performance of the counter-rotating type turbine was explored. The results show that the straight-ahead resistance of the UUV increased slightly after equipping the power generator, but the increase was within 14%, and the characteristics of the surrounding flow field of the UUV did not changed greatly. The difference in the linear hydrodynamic coefficients before and after equipping the UUV with the power generator was within 7%. At most drift angles, when the generator was in the working state, the yaw moment of the hull was greater than the condition when the generator was not equipped. Nevertheless, the overall trend of the two sides was similar, so the rotation of the counter-rotating type turbine did not reduce the stability of the hull in the moored state. In addition, when the drift angle was greater than 50°, the UUV hull had a great impact on the performance of the counter-rotating type turbine; the power coefficient CP and thrust coefficient CT increased by about 35.7% and 17.8%, respectively. This paper provides a good reference value for the design of the power generation mode of the UUV equipped with a counter-rotating type turbine.