Preflight Ground Test Analyses of the Boundary Layer Transition (BOLT) Flight Geometry

Abstract

heating was quantified using infrared thermography. Under quiet conditions, heat flux was characterized by a streak structure with no transition observed. Transition was observed within the conventional noise ACE facility in two regions: 1) in the vicinity of a mixed-mode structure and 2) in an outboard traveling crossflow region. The flow structure within a coherent vortex rollup located off centerline was further characterized under quiet flow conditions with constant-temperature hot-wire anemometry and high-frequency surface-pressure spectra. The measured mean and disturbance flow structure were in qualitative agreement with the simulations. The hot-wire spectral content showed growth in the 25-40 kHz range, which also agreed with the simulations. Surface-pressure spectral results showed similar growth in the 25-50 kHz range observed under both quiet and conventional freestream conditions.