复合材料水翼水动力响应数值模拟研究

In this paper, the characteristics of hydrodynamic damping and hydroelastic behavior of NACA0009 composite trapezoidal hydrofoil are studied by the fluid-structure coupling numerical model. The fluid flow numerical model, structural numerical model, fluid-structure coupling solution model, and wetted modal model of composite hydrofoil are established, and the modelis verified with experimental results. The modal results show that the laminated direction φ of the composite material affects the modal shapes of the hydrofoil. Compared with the φ=0° hydrofoil, the first modal frequencies of φ=+30° and φ=-30° hydrofoil decrease, and the second and third modal frequencies increase. Hydrodynamic damping is further investigated and the empirical relationship between the hydrodynamic damping ratio and the flow velocity is obtained. The hydrodynamic damping ratio of composite hydrofoil is proportional to the flow velocity, and the hydrodynamic damping ratio of φ=+30° and φ=-30° hydrofoil is larger than that of φ=0° hydrofoil. For the hydrodynamic load characteristics of composite hydrofoil at different flow rates, the results show that the steady hydrodynamic load coefficient of φ=+30° hydrofoil increases with the increase of flow rate, that of φ=-30° hydrofoil decreases with the increase of flow rate, and that of φ=0° hydrofoil slightly increases with the increase of flow rate. For the transient hydrodynamic load, the preliminary analysis shows that the hydrodynamic pattern is related to the ply angle. Compared with the flow velocity, the lamination angle has a greater influence on the distribution of transient hydrodynamic load. And the hydrodynamic force near the trailing edge of the suction surface of φ=+30° hydrofoil is greater than that of φ=0° hydrofoil.