Novel computer aided design of labial flue pipes

A labial flue pipe is a well known tone generator, which is familiar and easily recognisable as the organ pipes seen in many concert halls and churches. However, the design and understanding of the sounding mechanism of such pipes is fraught with difficulty. Traditionally labial pipes are constructed from age-old lookup tables that are closely guarded intellectual secrets. This paper discusses a novel computer program that facilitates the design and construction of such labial flue pipes. The computer program allows almost all aspects of the labial flue pipes design to be varied, the resultant frequency is generated and in addition the Ising efficiency number is provided. Furthermore, a discussion is included related to the fact that even though an Ising number greater than 3 indicates that a pipe is overblown, the fundamental tone is still predominant. A comparison will also be made between a CFD simulation of the labial flue pipe jet mechanism and smoke trail plots typical of such analysis.