The process of separation in the turbulent friction layer
A NASA technical report from 1933 on boundary-layer flow, offered here through the NASA Technical Reports Server as an engineering study of turbulent friction layers. The single picture is a chart of measured velocity-ratio curves plotted against a vertical axis, with each curve labelled by distance in centimetres from the surface. A designer might take from it the clean rising-and-flattening curve family and its restrained grid and labelling conventions as a model for technical data graphics.
