Experimental study of hypersonic boundary layer transition on a permeable wall of a flared cone

Abstract

The effects of an alternative permeable material on the hypersonic boundary layer transition are investigated. The new permeable material is shown to be effective in delaying the transition, although the second mode grows faster on the material surface. Experiments are conducted on a flared cone using Rayleigh-scattering flow visualization, fast-response pressure sensors, and infrared thermography. On the permeable wall, the second mode appears earlier and persists over a longer distance along the flow direction. By applying bicoherence analysis, it is determined that the second mode decays more slowly on the permeable wall due to weaker nonlinear interactions.