Abstract:
Elfyn Richards became the first Professor of Aeronautical Engineering at University College, Southampton, in September 1950 and he immediately began planning for jet noise research. The author joined him in January 1951, remaining until August 1956. Some events of that period are reviewed. With Richards' boundless energy and infectious enthusiasm, his indispensible help with more than a touch of impatience---kindly toward the author, less so for administrative barriers---progress was remarkably rapid, though the experimental apparati were in most respects very modest by later standards. The eighth power law for turbulent jet noise power (and the awkward lack of proportionality of peak frequency with velocity), the screech of choked jets and supersonic edgetones were all discovered in the first year. Feedback theories for the latter two, pulse jet noise, and other investigations such as shock wave interaction and means of reducing screech were soon to follow. Acoustically inducted fatigue (AIF) of aircraft structures caused by jet noise was predicted and soon after was found to occur in practice. Richards played some role in all of these topics, but his innumerable ideas and widening noise interests could not possibly all be addressed in that period.