Aerodynamic damping identification for aircraft models in transonic wind tunnels

During the transonic wind tunnel tests, vibration phenomena often appear on aircraft models, which has adverse effects on the wind tunnel test. This kind of vibration is often related to the modal damping information of the aircraft model. In this paper, the balance signal is used as the time-domain response of the aircraft model. Firstly, the random decrement method is used to extract the free vibration signal from the balance signal, and then the ITD method is used to estimate the modal damping parameters of the aircraft model. The effectiveness of the proposed modal damping estimation method is verified by the wind tunnel test data, and a comparative analysis is made with active damping system on and off. Based on the estimated aerodynamic damping information, corresponding measures can be taken to effectively avoid the vibration phenomenon that may occur during the wind tunnel test, and ensure the progress of the wind tunnel tests.