Dynamic Store Release of Ice Models from a Cavity into Mach 2.9 Flow

An investigation was conducted into store separation from a cavity in a Mach 2.94 freestream using both experimental and computational methods. Both approaches used an open cavity with a length-to-depth ratio of 4.5, and for the sake of simplicity, release of a spherical model was analyzed. The experimental process used a piezoresistive pressure transducer to collect the time-varying content of the pressure signal, while schlieren visualization and high-speed photography capture the dynamic response of a store released from the cavity. Computationally, the OVERFLOW solver was applied with higher-order numerical methods, Chimera grids, and the delayed detached-eddy simulation/shear-stress transport hybrid turbulence model. Tests were performed in a blowdown tunnel exhausting to a vacuum, which enabled robust control of the total pressure, and computational conditions were selected to match the experiment. The studies demonstrated that the shock wave formed on the bottom surface of the sphere led to the loss of vertical momentum for the sphere and, subsequently, its ascent back into the cavity for all but the lowest stagnation pressure conditions. Vortex-generating spoiler devices and an Mk-82 ice model were also experimentally tested to determine their effect, and the spoiler increased the vertical displacement of the store during separation, as expected.