Aeroelastic responses of spring-suspended airfoil systems in transonic buffeting flows
Computer simulations are performed to determine the responses of a single DOF pitch airfoil system, as well as those of a two DOF pitch-and-heave system, in buffeting flows. The buffeting flow exhibits shock-wave oscillations of a unique frequency that occurs for some combinations of mean flow angle of attack and transonic Mach numbers. It was found that frequency lock-in may occur, depending on the relationship between the buffet and structural frequencies. Following frequency lock-in the system response rapidly increases until reaching limit-cycle oscillations. Synchronization of the transonic aerodynamic buffet phenomenon and the structural elastic modes provides a physical mechanism that may be responsible for some aircraft transonic LCO occurrences. It is distinctly different from a flfluttermechanism, leading to LCO, as discussed in the manuscript. ©2012 AIAA.