Abstract
Active vibration control is the most effective method for stochastic multidimensional vibration in wind tunnel tests, in which vibration monitoring is the core foundation. Vibrations are induced by the disturbances of several complex air flow instabilities under extreme test conditions with high attack angles. Here, a decoupled unified observation method is proposed in order to fully monitor stochastic multidimensional vibration. First, stochastic multidimensional vibration is explained using the Cartesian coordinate system. Then, the multidimensional vibration decoupling of the pitch plane and the yaw plane is realized according to the proposed decoupling design principle of the long cantilever sting. A unified observation method is presented, based on inertial force theory, to observe multidimensional vibration due to acceleration in each decoupling plane. Verification experiments were conducted in lab and a transonic wind tunnel, using an established real-time monitoring system. The results of lab experiments indicate that, in the frequency region of 0–120 Hz, three vibration modes of a selected stochastic vibration can be decoupled and observed through the vibration components in pitch plane and yaw plane. In addition, wind tunnel tests were carried out according to the working conditions (α = −4~10° with γ = 45°) at Ma = 0.6 and Ma = 0.7, respectively. The results show that six vibration modes of two selected stochastic vibrations can be decoupled and observed through the vibration components in pitch plane and yaw plane. The experimental results prove that stochastic vibration can be fully monitored in multiple dimensions through the vibration components in pitch plane and yaw plane using the proposed decoupled unified observation method. Therefore, these results lay the foundation for active vibration control.
Highlights
High-speed aircraft, such as large passenger airplanes and military aircraft, are high-end pieces of equipment in the aeronautical and space fields
On the basis of dynamic theoretical analysis, the stochastic multidimensional vibration of the long cantilever support system can be uniformly observed in the pitch plane and the yaw plane, respectively
Using the proposed decoupled unified observation method, the stochastic vibrations caused by disturbances in complex unstable airflow were observed to be decoupled and monitored in all dimensions via the vibration components in the pitch and yaw planes under the working conditions (α = −4~10◦ with γ = 45◦ ) at Ma = 0.6 and Ma = 0.7, respectively
Summary
High-speed aircraft, such as large passenger airplanes and military aircraft, are high-end pieces of equipment in the aeronautical and space fields. Shen et al [15,16,17] selected the original voltage signal of a force or moment of six-dimensional aerodynamic load to monitor the pitch vibration of the aircraft model; two vibration modes were observed in the pitch plane. Only some of the vibration characteristics can be observed by intercepting single- or multidimensional force/moment in the active vibration control of the wind tunnel model. This leads to an unsatisfactory vibration control effect. Based on the theory of inertial force, multidimensional vibration is observed by acceleration time monitoring system and the performance of verification experiments.
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