Mitigation of vertical aerodynamic disturbances by means of a simple mechanical flap is investigated experimentally. A wall-to-wall NACA 0006 wing is bisected about the midchord for a 50%-chord flap length. Experiments are performed in a water tunnel at a chord-based Reynolds number of $Re=4\times {10}^4$. The wing is driven in a sinusoidal vertical plunge motion as a spatially uniform, temporally varying surrogate to a vertical disturbance. Concurrently, the flap is actively deflected in a survey of kinematic parameters designed to suppress the influence of a plunge-induced disturbance. Plunge rates explored amount to disturbances incurred over a temporal range from one convective time to eight convective times. Two methodologies are employed to guide selection of flap deflection phase and amplitude necessary to preserve the baseline zero-lift state ($\alpha =0°$) of the undisturbed wing. In the first method, Theodorsen’s model is applied to arrive at an analytical solution to flap kinematics for a given prescribed plunge history. The theoretical derivation makes the standard assumptions of attached flow, planar wake, and no leading-edge vortical formations. Direct force measurements reveal reduction in lift transients by flap actuation of up to 87%, verifying the applicability of Theodorsen’s classical model. Further improvement is sought in a second method where empirical state-space modeling is formulated for lift cancellation. In this approach two separate lift models for wing plunge and flap deflection are constructed independently, and their superposition is employed to approximate the total lift in combined plunge and deflection motions. It is shown that although the empirical state-space approach performs similar to the inviscid theory of Theodorsen’s model, the empirical model proves more effective in suppressing the formation of the leading-edge vortex induced by plunge.

通过实验研究了通过简单的机械襟翼减轻垂直空气动力扰动的方法。壁到壁的 NACA 0006 机翼在中弦附近被一分为二，以获得 50% 的弦襟翼长度。实验是在基于弦的雷诺数的水隧道中进行的$\mathrm{电阻}\mathrm{电子}=4\times {10}^4$. 机翼以正弦垂直俯冲运动驱动，作为垂直扰动的空间均匀、随时间变化的替代物。同时，襟翼在运动学参数的调查中被主动偏转，以抑制暴跌引起的干扰的影响。探索的骤降率相当于在从一次对流时间到八次对流时间的时间范围内发生的扰动。采用两种方法来指导选择襟翼偏转相位和幅度，以保持基线零升力状态（$\alpha =0°$) 不受干扰的机翼。在第一种方法中，Theodorsen 的模型被用于为给定的规定下沉历史得出襟翼运动学的解析解。理论推导做出了附加流、平面尾流和无前缘涡旋形成的标准假设。直接力测量显示，襟翼致动使升力瞬变减少了 87%，验证了 Theodorsen 经典模型的适用性。在第二种方法中寻求进一步改进，其中为升力抵消制定经验状态空间建模。在这种方法中，机翼俯冲和襟翼偏转的两个独立升力模型是独立构建的，并且它们的叠加被用来近似组合俯冲和偏转运动中的总升力。