The boundary layer as a means of controlling the flow of liquids and gases
A 1930 technical report from the NASA Technical Reports Server, a scientific paper on boundary layer control of fluid flow, written for aerodynamics engineers and researchers. Its pictures are plain line graphs and diagrams: two charts plotting pressure and lift coefficients against angle with curves labelled a and b, and a sketch of a wing held between wind-tunnel guide lines, which a designer might use as a clean, schematic model for technical diagrams.
