Numerical simulation of hydrodynamic and noise characteristics for a blended-wing-body underwater glider

The present study compares the hydrodynamic and noise characteristics of a second-generation underwater glider, i.e., the blended-wing-body glider, and a traditional Slocum glider, based on large eddy simulation and Ffowcs-Williams and Hawkings equation. Results shows that the blended-wing-body glider has a maximum lift/drag ratio of 15.38, which is significantly higher than that of the traditional glider (5.84 for the Slocum), suggesting that the blended-wing-body glider is lower-energy-cost. In terms of the underwater radiated noise, the maximum noise of both gliders is located in the direction above/below the glider. In the designed working conditions, the maximum sound pressure level of the blended-wing-body glider is found to be 64.78 dB, which is significantly lower than that of the Slocum (91.49 dB). This finding indicates that the blended-wing-body glider is suitable for ocean acoustic observation tasks compared with the traditional glider (a revolving body combined with two wings, such as the Slocum glider), thanks to its excellent low-noise performance.