A suggested method for measuring turbulence
A 1931 aeronautical technical note from the NASA Technical Reports Server, produced for engineers and researchers studying airflow, proposing a method for measuring turbulence. Its pictures are plain line graphs with no decoration: a curve rising to a sharp peak labelled smooth and turbulent, falling curves numbered 1 and 2, a family of bell-shaped sensitivity curves plotted against angle on dial for several air speeds, and a scatter of circles and crosses along a descending curve. A designer could take their clean, restrained chart language, with thin single-weight lines, sparse labels and paired curves, as a model for minimal data graphics.
