复合材料水翼水动力响应数值模拟研究

Numerical investigation of hydrodynamic response of composite hydrofoil

该文针对NACA0009复合材料梯形水翼进行流固耦合数值计算,研究复合材料水翼水力阻尼及水弹性响应特性。研究建立了复合材料水翼流场模型、结构模型、流固耦合计算模型及湿模态模型,并利用实验结果对模型进行验证。模态分析结果表明:复合材料铺层角φ影响水翼模态振型,相比于φ=0°铺层,φ=+30°铺层和φ=-30°铺层水翼的一阶模态频率降低,二阶和三阶模态频率升高。研究进一步对水翼振动过程的阻尼特性进行分析,得到了水力阻尼比与流速的经验关系式,复合材料水翼水力阻尼比与流速成正比,且相比于φ=0°铺层,φ=+30°铺层和φ=-30°铺层水翼的水力阻尼比更大。分析了不同流速下复合材料水翼的水动力载荷特性:对于稳态水动力载荷,φ=+30°铺层水翼的载荷系数随流速增加而增大,φ=-30°铺层随流速增加而减小,φ=0°铺层随流速增加而略有增加;对于瞬态水动力载荷,初步分析表明,水翼受到的水动力作用形式与铺层角相关:相较于流速,铺层角φ对瞬态载荷分布的影响更大,且φ=+30°铺层水翼吸力面尾缘附近所受水动力比φ=0°铺层更大。

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 model is verified with experimental results.The modal results show that the lam inated directionφof the composite material affects the modal shapes of the hydrofoil.Compared with theφ=0°hydrofoil,the fi rst modal frequencies ofφ=+30°andφ=-30°hydrofoil decrease,and the second and third modal frequencies increase.Hydrodyn amic damping is further investigated and the empirical relationship between the hydrodynamic damping ratio and the flow velo city is obtained.The hydrodynamic damping ratio of composite hydrofoil is proportional to the flow velocity,and the hydrodyn amic damping ratio ofφ=+30°andφ=-30°hydrofoil is larger than that ofφ=0°hydrofoil.For the hydrodynamic load characteri stics of composite hydrofoil at different flow rates,the results show that the steady hydrodynamic load coefficient ofφ=+30°hydrofoil increases with the increase of flow rate,that ofφ=-30°hydrofoil decreases with the increase of flow rate,and that ofφ=0°hydrofoil slightly increases with the increase of flow rate.For the transient hydrodynamic load,the preliminary analysis shows t hat the hydrodynamic pattern is related to the ply angle.Compared with the flow velocity,the lamination angle has a greater influe nce on the distribution of transient hydrodynamic load.And the hydrodynamic force near the trailing edge of the suction surf ace ofφ=+30°hydrofoil is greater than that ofφ=0°hydrofoil.