Computation of Three-Dimensional Nonlinear Panel Flutter

A recently developed three-dimensional viscous aeroelastic solver is applied to the solution of nonlinear panel flutter. The solution scheme implicitly couples a well validated Navier-Stokes code with a finite-difference procedure for the Von Karman plate equations by employing a subiteration strategy. Both low supersonic, M∞=1.2, and subsonic, M∞=0.95, cases are computed. For the supersonic case, the presence of either a laminar or turbulent boundary layer delays the onset of flutter, with higher flutter dynamic pressures resulting for thicker boundary layers. This effect is much less pronounced when the boundary layers are turbulent. In the subsonic case multiple solutions are obtained. The downwardly divergent solution displays a very complex interaction between the laminar boundary layer and the flexible panel that results in significant acoustic radiation from the vibrating panel.