Experimental Investigation of Supersonic Fluid-Structure Interaction for Future Space Transportation Systems

Kurzfassung

Efficient orbital launch vehicles require a weight-optimized structure that can reliably withstand severe aerothermodynamic loads. The relevant loads, which are crucial for the design of such light-weight structures, can depend on the interaction of the thermal and deformation state of the structure with the surrounding flow field. This is referred to as Fluid-structure interaction (FSI). The reliable prediction of these loads is difficult, both for simplified engineering models and highfidelity models, because such FSI problems are typically non-linear and, in many cases, dependent on turbulence. To improve fundamental understanding of such problems and to provide validation and reference data for modelling, a set of wind tunnel experiments was conducted where thin elastic panels were subjected to super- and hypersonic flow conditions ranging from cold conditions at high Reynolds numbers to high-enthalpy conditions. The experiments were conducted in the wind tunnels TMK, H2K, and L3K at DLR, Cologne. The observed behaviors of the panels include structural dynamics driven by the intrinsic dynamics of Shock-wave/boundary-layer interaction (SWBLI) and also by prescribed incident shock movements, panel flutter with and without SWBLI, and thermal buckling, in some cases with plastic effects. Cases combining both temperature- and pressure-driven effects were used to study the influence of the thermal and buckling state of the structure on structural dynamics. The experiments were accompanied by reference measurements on rigid wall structures to characterize thermal and pressure loads. The results of this study enabled a detailed analysis of the behavior of structures in super- and hypersonic flow environments, and also their influence on the flow field. Several data sets from these experiments have already successfully been used for comparison to numerical simulations.