NON-CLASSICAL FLOW-INDUCED RESPONSES OF A LIFTING SURFACE DUE TO LOCALIZED DISTURBANCES

摘要

A non-classical aeroelastic response due to a localized disturbance on a lifting surface has been investigated employing a transient aerodynamic strip theory at subsonic speeds. It is demonstrated that both parametric and combination resonance instabilities can exist on a lifting surface structure with localized aerodynamic disturbances which cause in-plane periodic air loads in the region of the disturbance site. A matrix of aerodynamic lag influence coefficients is included to seek a complete description of the transient characteristics of these instabilities. Comparisons with quasi-steady aerodynamic modeling show that, although there are some changes in the regions of instability, qualitative agreements do occur. The mechanism causing the localized time-dependent aerodynamic disturbance is specified as a localized damage to the lifting surface. Other candidate mechanisms, however, include localized unsteady shock patterns or external wing stores.