The Interaction Between Shock Buffet and Freeplay Nonlinearity: A Numerical Investigation

The aeroelastic interaction between shock buffet and freeplay-induced nonlinear structural dynamics has not yet been studied in the literature. This paper presents preliminary findings on the topic, focusing on numerical simulations of a two-degree-of-freedom heave-pitch aeroelastic airfoil with pitch freeplay. The results demonstrate that when the freeplay angle is sufficiently large, nonlinear resonance can occur if the ratio of the heave mode natural frequency to the shock buffet frequency (Formula Present). Specifically,aerodynamicforcesexhibitlock-intotheheave mode superharmonic 2 fh which leads to a 2:1 resonance, 8.4., with the heave and pitch modes oscillating at fh.