Driving Mechanisms of High-Speed Unsteady Spiked Body Flows, Part 2: Oscillation Mode

摘要

The driving mechanism of the unsteady flow mode oscillation, arising over spiked bodies, was analyzed by using computational fluid dynamics as a tool. Laminar, axisymmetric flow at Mach 6.00 and Reynolds number (based on the blunt-body diameter) of 0.13 x 10~4 was simulated by a spatially and temporally second-order-accurate finite volume method. The model geometry was a forward-facing cylinder of diameter D equipped with a spike of length L/D = 2.00. Verification and validation of the numerical method are followed by a detailed analysis of the numerical results. It was found that, apart from some minor modifications, the oscillation flow mode was driven by the energetic shear-layer hypothesis of Kenworthy (Kenworthy, M., "A Study of Unstable Axisymmetric Separation in High Speed Flows," Ph.D. Dissertation, Dept. of Aerospace and Ocean Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA, 1978), a viscous phenomenon in nature.