On the nonlinear structural damping mechanism of the wing/store limit cycle oscillation

摘要

Contrary to previous belief, our recent study along with factual observations of the F-16 have indicated that a nonlinear transonic aerodynamic (NL Aero) model cannot represent the sole mechanism for wing/store limit cycle oscillation (LCO). ^Rather, we found that a nonlinear structural damping (NSD) model based on dry friction, a largely overlooked component, would more likely be an individual or collective (with NL Aero) cause of LCO over much wider Mach ranges than transonic LCO. ^Additional rationales also suggest that priority should be given to NSD research instead of NL Aero investigations. ^Towards this end, two research plans are recommended, i.e., to develop an LCO prediction methodology using simpler aerodynamics with NSD, and to pursue the understanding of LCO using high-level CFD with NSD. ^Seven technical goals are proposed to address the basic research issues for Plan 1, with particular emphasis on the identification of the Coulomb friction in the wing/store system. ^It is recommended that the example cases set up by both plans should ultimately be validated with rigid F-16 wind-tunnel data yielding flutter and with F-16 flight tests indicating LCO. ^(Author)