Research on an active pitching damper for transonic wind tunnel tests

Abstract

In wind tunnel tests, the sting with a model and a balance installed forms an elastic beam. To reduce the aerodynamic interference, the slenderness ratio of the sting is usually small, which obviously results in low damping of the whole structure. In that case, violent oscillation appears quickly while the sting is exposed to varying aerodynamic loads, which finally leads to inaccurate data and even damage to the structure. In this paper, the vibration of the model-balance-sting system was analyzed experimentally, and the concepts of active pitching damper were detailed in this paper. Based on independent modal space control, linear quadratic regulators were designed with identified state-space models. The active pitching damper was successfully validated by exerting impulse loading in model preparation bay firstly and then tested in a transonic wind tunnel. Experimental results show that the maximum attenuation of vibration reached 91% in standard deviation and extension of the angle of attack was 6°. Moreover, wind tunnel tests proved the effectiveness of the active pitching damper working on different test configurations, which indicates the superiority of the damper.