Vortex Noise from Rotating Cylindrical Rods
This is a 1935 technical note from the National Advisory Committee for Aeronautics, issued through NASA's Technical Reports Server, reporting measurements of vortex noise from rotating cylindrical rods for an aeronautical research audience. The pictures are plain engineering charts: oscilloscope traces of frequency spectra at several rotational speeds, a log-scale line graph, a pressure distribution curve, a polar diagram of sound pressure around the rod, and a sound pressure versus tip speed plot. A designer could take from them the stark, grid-based graphic language of early scientific instrumentation, with wave-like traces and radial plots as abstract motifs.
