半转翼的Weis-Fogh效应及推力的仿真研究

针对仿生飞行研究中具有重要应用前景的新型动力翼—半转翼的推力计算问题,提出了一种半转翼模型,导出了该模型参数的计算方法;基于XFLOW建立了两个半转翼CFD模型,即无固壁和有固壁半转翼模型,通过选择合理的流场计算区域和边界条件,采用湍流计算模型和刚性翼运动模型,结合半转翼实验模型参数和运动参数对半转翼流场速度、压力分布及推力进行了数值计算,获得了Weis-Fogh效应对半转翼运动流场特性和半转翼推力的影响规律,并与一个运动周期的实验推力进行了分析比较。研究结果表明:有固壁的半转翼流场中速度分布始终受到"急张"和"相拍"的影响,可大大提高半转翼的推力;由半转翼-固壁模型获得的推力计算曲线能真实反映半转翼推力的变化规律,这对计算不同参数的半转翼-固壁模型的推力具有参考价值。

Numerical simulation of propulsion of half-rotating wing with Weis-Fogh effect

Aiming at the thrust computation of half-rotating wing as a new power wing to be applied in bionic flying,a model of the half-rotating wing was proposed and the formulas to calculate the model parameter were derived.The two CFD models,wings with fixed wall and no wall,were established based on XFLOW with reasonable computed area and boundary condition of the flow field,turbulent flow model and complex motion of rigid wings.The numerical simulation was made using the same parameters and inputs in a experimental model of the halfrotating wing to obtain the flow field characteristic of the two CFD models and the wing's propulsion affected by Weis-Fogh effect.The computed thrust was compared with experimented thrust in same conditions in all of motion period of the wing.The results indicate that the wing lap and fling always act on the velocity distribution in the flow field around the wing with fixed wall so as to greatly increase the wing thrust.The computed thrust from the models presented above can demonstrate real change of the wing thrust.These provide important reference for the thrust estimation of different parameter models with fixed wall.