The Frictionless Flow in the Region Around Two Circles
This is a 1931 technical report from the NASA Technical Reports Server, a mathematical treatment of frictionless fluid flow around two circular cylinders, written for aerodynamic and hydrodynamic researchers. Its pictures are line diagrams of complex-plane contours: a periodic rectangle with labelled circulation paths in Fig. 3, and circle-to-rectangle transformation sketches with labelled axes and loops in Figs. 2a and 2b, which a designer might use as spare geometric linework for technical or scientific layouts.
