Effectively analyzing aeroelastic model empirical design for empennage non-lift type buffeting and its wind tunnel test data

There exist already some aeroelastic model empirical designs for empennage non-lift type buffeting but how to analyze their wind tunnel test data effectively appears to remain an unsolved problem. Northwestern Polytechnical University has engaged in aeroelastic research for decades and, based on our experience, we propose a buffeting characteristic index, which we believe can analyze effectively wind tunnel test data for such buffeting. Aircraft empennage non-lift type buffeting is a typical dynamic aeroelastic response phenomenon which is usually excited by nonlinear aerodynamic forces in turbulent or separated wake flow which is induced by blunt body installed on the aircraft fuselage. Flight tests and wind tunnel tests are often used to study this aeroelastic problem to avoid the difficult aerodynamic force calculation. We just list the topics of our explanation; (1) empirical design and building of our aeroelastic model for empennage non-lift type buffeting; (2) wind tunnel tests of our model; (3) effective analysis of wind tunnel test data with the above mentioned buffeting characteristic index; this index is denoted by r and r = ̃ε_b/̃ε_s, where ̃ε_b is the mean-square strain at the fin root caused by its dynamic response with blunt body on the fuselage, e, is that without blunt body. -Fig. 4 in the full paper gives the variations of characteristic index r with the pitch angle θ in the range of θ = -10° to θ = 10° for four different values of yaw angle φ: 0°, 2.5°, 5°, and 8°. The four curves in Fig. 4 show that yaw angle has little effect on the characteristic of empennage non-lift type buffeting while the pitch angle has considerable impact on it. The effective analysis using characteristic index r shows preliminarily that our empirical design of aeroelastic model for non-lift type of buffeting is fairly satisfactory.