惯性参数对飞翼体自由度颤振特性的影响规律研究

飞翼飞行器刚体短周期模态频率较高,易与一阶弹性弯曲模态耦合发生一种特殊的颤振——体自由度颤振。采用风洞实验与频域计算相结合的手段,开展了惯性参数(俯仰转动惯量、质心位置)对飞翼飞行器体自由度颤振特性(颤振速度和颤振频率)的影响规律研究。实验和计算结果表明:俯仰惯量和质心位置会明显改变体自由度颤振频率与速度,颤振实验与计算结果一致性较好。俯仰惯量增加,颤振频率降低,沉浮约束时颤振速度基本不变,沉浮自由时颤振速度增大;质心位置前移,俯仰模态频率与阻尼同时增加,俯仰与一阶弹性弯曲模态耦合更容易,但发散模态分支的阻尼也更大,导致颤振速度先降低后增大,颤振频率单调增加。

Influence of inertial parameters on body freedom flutter of flying wings

The rigid body short-period mode of flying-wing aircrafts is prone to couple with the first-order elastic bending mode,which will result in the body freedom flutter that is still not well understood yet.The influence of inertia parameters(pitching inertia and center of gravity)on characteristics(flutter velocity and flutter frequency)of the body freedom flutter of a flying-wing aircraft is studied by wind tunnel experiments and frequency domain calculations.The results of experiments and calculations,which agree well with each other,show that the pitching inertia and the center of gravity can change the frequency and velocity of the body freedom flutter substantially.With the increasing of the pitching inertia,the frequency of the pitching mode decreases.While the flutter velocity remaines unchanged under the constraint of plunge degrees of freedom and increases otherwise.When the center of gravity moves forward,the frequency and damping of the pitching mode both increase.The pitching mode and the first-order elastic bending mode are more likely to couple.But the damping of the divergent mode branches is larger,so that the flutter velocity first decreases and then increases,while the flutter frequency increases monotonously.