Store-Cavity Separation in Mach 5 Flow: Fluid-Structure Interaction of a Single Degree-of-Freedom Store Model

Separation events within high-speed flight introduce complex aerodynamic forces that can affect vehicle flight trajectories. When coupled with hypersonic vehicles that have a high slenderness ratio, these separation events can significantly alter the vehicle's structural response and consequently alter its trajectory as well. The fluid-structure interaction of a structurally-compliant slender axisymmetric model at different stages of store-cavity separation is experimentally investigated in a Mach 5 blowdown wind tunnel. The model is comprised of a 5-degree half-angle rigid cone attached to a rigid cylinder by using an elastic flexure element to provide a single degree-of-freedom in the motion of the cone. Z-type schlieren is used to characterize major flow structures at different transverse (wall-normal) locations of the sting-mounted store with respect to the open cavity. Simultaneous high-speed pressure-sensitive paint and laser Doppler vibrometer measurements are used to explore the multi-physics nature of the model's fluid-structure interaction. In particular, we will focus on the coupling of the unsteady surface pressure field to the structural dynamics when the model interacts with the cavity shear layer. Important flow characteristics will also be compared between both the compliant and the rigid store models.