Charbel Farhat, University of Colorado, Boulder
Flutter is an instability problem where an unbounded oscillation in time of a structure is caused by the high-speed passage of air along or around it. Because of the potentially disastrous character of this phenomenon, aircraft flutter is expected to be eliminated by design. Nevertheless, flight flutter testing is always performed to verify a design. Today, the aerospace industry predicts this aeroelastic problem by fast linear computational methods that perform well in the subsonic and early supersonic regimes, but are not reliable in the transonic regime. For this reason, it was recently suggested that the results of nonlinear CFD-based multidisciplinary solutions could be used as a replacement for wind tunnel testing, assuming they can be obtained in less than one year and using a validated nonlinear aeroelastic code.
The speaker will report on a research effort conducted at the University of Colorado, in collaboration with the Flight Test Center at the Edwards Air Force Base, to meet this challenge as well as innovate flutter flight testing. He will discuss recent advances in CFD on moving grids, state-of-the-art, loosely-coupled, and massively parallel algorithms for the solution of nonlinear fluid-structure interaction problems, and the combination of these computational technologies with reduced-order modeling schemes to enable real-time prediction of flutter. He will also report on the results of a validation effort for two F-16 and F-18 fighter jet configurations.