Nonlinear Dynamics of Prestressed Panels in Low Supersonic Turbulent Flow

Kurzfassung

It is known that the aeroelastic stability of elastic plates significantly decreases in low supersonic flow. A further reduction may arise due to compressive in-plane loads, which can be caused by deformations of the adjacent structure. Thus, this is an important subject in the design of supersonic aircraft or rockets. Encouraged by recent studies that have shown an increase in aerodynamic damping due to a turbulent boundary layer, the present study applies three different aerodynamic models coupled with the von Kármán plate equation to show that there is as well a significant enlargement of the static stability regions of a flat plate subjected to quasi-static in-plane loads at Mach 1.2. However, it has also been found that, despite a turbulent boundary layer, the critical dynamic pressure for flutter almost drops to zero if the in-plane load approaches the critical load for Euler buckling. Further analysis on postcritical flutter revealed that a flexible panel subjected to a boundary layer behaves similarly to a panel in inviscid flow at a lower dynamic pressure, leading to the conclusion that the turbulent boundary layer scales down the effective dynamic load. This result further shows that the aeroelastic design of flexible plates based on inviscid flow models is a conservative approach. Representative results have been discussed by means of bifurcation curves, modal participation analysis, frequency spectra, phase plots, and Poincaré maps.