Development and validation research of an active sting damper in a transonic acoustic wind tunnel
In wind tunnels, the support systems holding up the aerodynamic models under testing, such as long cantilever stings, confer a reduction of airflow interference on experiment data. Nevertheless, given the low structural damping of the support systems, such support systems could adversely turn out to be the potential source of vibration, which makes the aerodynamic model testing vulnerable to test envelop limitation and datum quality degradation. Model flow separation and turbulence in wind tunnel could stimulate the low order resonant modes of a sting structure, leading to detrimental vibration. The presented research elaborates on the development and control strategy of an active sting damping system employing piezoelectric stack actuators and balance signal feedback. The experiments implemented both in laboratory and transonic wind tunnel environment reveal the consistency between designed vibration suppression target and experiment results, and assert the verification of control algorithm. It is demonstrated that the active sting damper, regulated by PD controller, has attenuated the oscillation with effect. For sting mode only, 90% energy elimination of sting mode frequency has been attained; moreover, the operational range of angle of attack has been expanded by 1.5 degrees.