Investigation of boundary layer transition at high Reynolds numbers using time-resolved temperature-sensitive paint

Abstract

A fast-response temperature-sensitive paint is used to investigate unsteady transitional phenomena on a flat plate at high Reynolds numbers in a compressible subsonic flow at the Cryogenic Ludwieg-Tube Göttingen (KRG). Using high camera acquisition rates of up to 40 kHz, the quantitative and time-resolved temperature and heat-flux distributions were determined. This allowed for the investigation of transition location, intermittency distribution, steady and intermittent turbulent wedges and turbulent spots. For turbulent spots, properties like propagation celerities, shape, merging behavior and spreading angles were determined in a systematic study of flow conditions for the first time using a thermographic surface measurement technique.