Some Experimental Results on Dynamic Aeroelasticity of Plates and Shells in Subsonic and Supersonic Flow

Kurzfassung

Shells and plates exposed to supersonic flow can be subject to dynamic aeroelastic instability called panel flutter, which is caused by the elimination of the system’s damping. This is initiated by aerodynamic loads induced by initial structural motions. Experimental activities on this subject were performed by DLR Institute for Aeroealsticity at DNW Transonic Wind Tunnel in Göttingen on rectangular and flat plates. Besides the aerodynamic parameters Mach number and Reynolds number, structural parameters, such as amplitude and excitation frequency, were varied for two simulated modal shapes by means of a forced excitation approach. Unsteady pressure and deformation measurements were done in order to determine the local aerodynamic responses evoked by the structure’s oscillating deformation and based on that Generalized Aerodynamic Forces. The excerpt of those tests that is presented in this paper focuses on the Mach number’s impact, which is varied in a range of 0.7 < M ∞ < 1.2, on the pressure response and the resulting aerodynamic damping. For validation analytic approaches for high supersonic and low subsonic flow conditions are applied. Elaborate knowledge about the non-linear aeroelastic behaviour in the high subsonic and low supersonic flow domain may lead the way to less conservative designed and thus light weight designed aerospace structures. A contribution to sustainability follows due to resulting savings in mass and fuel.