(b Cleveland, OH, July 19, 1915; d Pittsburgh, PA, Feb 10, 2010). American scientist and acoustician. After studying physics at Case Institute of Technology (BS 1937), he carried out research in nuclear physics at the University of Illinois (PhD 1941). He then joined the Westinghouse Electric Corporation, remaining with the firm for the rest of his professional life; he retired in 1980 after a distinguished career culminating in six years as Director of Research and Development. In his youth he had become an accomplished flute player, and during his undergraduate studies at Case he encountered the notable acoustician Dayton C. Miller. This meeting led to a lifelong interest in the acoustics of the flute, and Coltman developed a laboratory at his home in which he conducted many important and illuminating experiments on flutes and flute playing. Particularly significant was his contribution to the understanding of the subtle interaction between the air jet blown across the flute embouchure hole by the player and the resonances of the air column within the flute pipe. Over four decades, starting in the mid-1960s, he published more than 40 papers on the acoustics of flutes and organ pipes. He was a member of the National Academy of Engineering and a Fellow of the American Physical Society and the Institute of Electrical and Electronic Engineers....
In the terminology of organ building, a flue pipe in which the end remote from the mouth is closed by a movable stopper or airtight cap. This provides a means of tuning.
In general, a stopped pipe is any tube that communicates freely with the ambient air at one end and is completely closed at the other. The Air column in such a tube will vibrate with an antinode at the open end and a node at the closure. The fundamental is approximately an octave lower than that given by a pipe of equal dimensions open at both ends, and its wavelength is four times that of the tube itself. The harmonic series of a stopped pipe lacks the even-numbered partials; Overblowing begins a 12th above the fundamental. Because it shows this characteristic the clarinet is sometimes loosely termed a stopped pipe. Among folk instruments the stopped pipe is represented by many end-blown flutes of varying degrees of sophistication....