Laminar-Turbulent Transition in High-Speed Compressible Boundary Layers: Continuation of Elliptic-Cone Experiments

摘要

This grant supported experimental research into high-speed laminar- turbulent transition. While it began as a one-year effort extending our earlier work on elliptic cones, it became increasingly evident that the low quiet Reynolds number available in the Mach-4 quiet Ludwieg tube was limiting the usefulness of the measurements. Although useful results for instability and transition were nevertheless obtained, the emphasis shifted toward development of a high Reynolds number Mach-6 quiet Ludwieg tube. Instrumentation development also continued, in the form of a series of experiments carried out at low quiet Reynolds number in the existing Mach-4 Ludwieg tube. Experiments with the laser perturber, glow perturber, hot wire, laser-differential interferometer, and hot films are summarized. These experiments were carried out on elliptic cones, round cones, and a scramjet-inlet model.