ASA 125th Meeting Ottawa 1993 May

4pMU6. Measurement of flow rate past a clarinet reed.

Fang-Chu Chen

Gabriel Weinreich

Randall Lab. of Phys., Univ. of Michigan, Ann Arbor, MI 48109-1120

The relation of the air flow through a clarinet mouthpiece to the pressure difference across it and the size of the read opening has been investigated by connecting the mouthpiece to an air reservoir that is pumped to a partial vacuum and allowed to fill through the mouthpiece. The pressure in the reservoir is measured ten times per second until atmospheric pressure is restored. In principle, the rate of change of pressure determines the rate of air flow, so that the desired relationship is obtained. One difficulty comes from an ignorance of the reservoir air temperature, since completely adiabatic conditions cannot be assumed. Another is that the rate of change of pressure is sometimes too large to assure internal equilibrium of the reservoir gas. There is a plan to eliminate the first difficulty by adding an independent temperature sensor, and to alleviate the second by using a larger reservoir. Preliminary measurements, including comparison with results in the literature, will be presented. [Work supported by NSF.]