Dynamic stability characterization of re-entry modules at hypersonic mach numbers

摘要

At the time of re-entry modules entering into the atmosphere from space, a small perturbation introduces dynamic oscillations on the vehicle because of their extreme traveling speed. The dynamic stability characteristics of re-entry modules at hypersonic Mach numbers is of considerable relevance to their initial design. In the present paper, the dynamic stability of blunt cone model about 10° is examined with wide range of design parameters such as nose bluntness, semi-vertex angle and center of rotation through theoretical and experimental methods. Theoretical approximations are made over a model based on the standard Newtonian theory. Experiments are conducted at 0.25 m hypersonic wind tunnel at M = 8.3 and the following trends are observed from the experimental analysis. Interestingly, the incremental higher nose bluntness, semi-vertex angle and center of rotation reduce the dynamic stability. At higher hypersonic Mach numbers (M > 10), dynamic stability characteristics of the re-entry module are insensitive to the free stream Mach number. However, it is observed that the dynamic stability is increased in proportion to the vibration amplitude at hypersonic speeds.