The influence of roughness trips upon boundary-layer transition. I - Characteristics of wire trips

Extended data are presented on the flow past roughness trips provoking boundary layer transition, with attention to the forces on the wire, the positions of recovery and effective origin of the turbulent layer, the length of the separation bubble, and the beginning and end of transition. Values of the bubble length were successfully correlated over a range of pressure gradients; this length is noted to be related to the location of the start of transition.