Freedrop Testing and CFD Simulation of Ice Models from a Cavity into Supersonic Flow.

摘要

Weapon release at supersonic speeds from an internal bay is highly advantageous. For this reason, both experimental and numerical methods were used to investigate store separation from a cavity (L=D=4.5) into Mach 2.94 ow. The experiment used a piezoresistive pressure transducer, Schlieren and high- speed photography for data acquisition. The computational solution used the OVERFLOW solver. A sphere and a Mk-82, scaled to 1:20, were formed using frozen tap water. The sphere model was freedrop tested experimentally and computationally, while the sub-scale store shaped model was freedrop tested experimentally. The total pressure was varied to alter the dynamic response of the model. Computed spectra of pressure signals were in reasonable agreement with those measured experimentally, while the trajectory and dynamics of the CFD sphere release closely matched the experiment. Two sawtooth spoiler devices were tested for e ectiveness at high Mach numbers. Pressure measurements showed a detuning of the Rossiter tones but with an increase in the broadband levels. Furthermore, spoiler testing demonstrated the capability to enhance store separation. Mk-82 shapes were also tested, which proved that the experimental process can be used with representations of actual stores. Reducing the test pressure conditions to sub-atmospheric levels allowed sub-scale models to be accurately scaled in mass and moment of inertia using heavy Mach scaling laws.