Design and Aerodynamic Analysis of Rigid Wing Sail of Unmanned Sailboat at Sea Based on CFD

As a novel type of ocean monitoring tool, unmanned sailboats exhibit significant application potential. In this study, a novel wing sail structure for offshore unmanned sailboats is proposed and its performance compared with that of the conventional NACA 0021 wing sail. The Reynolds-averaged Navier–Stokes (RANS) equations are employed for numerical analysis, and the aerodynamic performance is evaluated using ANSYS Fluent. The results indicate that the lift coefficient and lift-to-drag ratio of the HF-14-CE-01 wing sail are significantly superior to those of the NACA 0021 wing sail. Compared to the NACA 0021 wing sail, the HF-14-CE-01 wing sail has undergone structural optimization. The HF-14-CE-01 wing sail demonstrates improved wind direction efficiency, uniform force distribution, ease of adjustment, and extends the service life of the sail. Subsequent research examined the influence of aspect ratio on both the aerodynamic performance of the wing sail and the thrust generated by the unmanned sailboat, identifying an optimal aspect ratio of 4 for the HF-14-CE-01 wing sail. Analysis of the velocity and static pressure contour maps for the HF-14-CE-01 wing sail identified a critical angle of attack of 28°, providing a clear visual representation of its aerodynamic performance. Furthermore, compared with other rigid sail designs, the HF-14-CE-01 wing sail achieved a 30.9% increase in peak lift coefficient, indicating superior propulsion capability.