针对脉冲型风洞有效试验时间短、测力天平输出为大幅振荡信号的问题,提出了一种从振荡信号中提取稳态值的方法.忽略风洞启动段的数据,只取来流稳定段上的天平测力信号,将其看作是因受恒定载荷作用而处于非零稳态位置的多自由度系统由未知初始位移和速度引起的自由振动响应,用参数化的自由振动模型拟合测量输出,通过求解优化问题辨识出未知参数,其中就包含了所求的天平稳态输出值.用几个算例对方法进行了检验.%An impulse tunnel can only provide a flow with very short testing period,and the outputs of force balance are oscillatory signals with large amplitude.A new method was proposed to recover the steady-state value from the oscillatory signal.The balance's signals over the initiation period of the tunnel were omitted and only the signals over the steady testing period were adopted for analysis.This segment of the balance's signals was regarded as free vibration responses of a multi-degree-of-freedom system caused by initial displacements and velocities,and the system was originally in a non-zero steady state supported by constant loads.The free vibration response was formulated with unknown parameters,and an optimization problem was constructed by minimizing the deviation of theoretical response from the measured response.The unknown parameters including the steady-state value of the balance's output could be estimated by solving the optimization problem.Finally the effectiveness of the proposed method was demonstrated by several application examples.
展开▼
