Jet-Driven Instruments and the Edgetone.
CITY UNIV OF NEW YORK
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On the basis of observations due to Coltman and Powell a simplified linear, small, signal model of jet action in jet-driven instruments and the edgetone is presented. The model leads, by means of an elementary phase analysis, to very simple and intuitive pictures of the feedback models of Powell and Cremer and Ising. For jet-driven instruments the sole demand that the jet deflection at the edge be in phase with the orifice volume-displacement, without impedance or any other analysis, implies the surprisingly accurate formula f .4 micron2h for the fundamental frequency f, with jet velocity micron and orifice-edge distance h. For the edgetone, the sole demand that the transverse displacement at the orifice lag the jet deflection at the edge of Pi2 Powells assertion implies the formula for the frequency of the edgetone operating in the k-th stage, f .4micronhk14, which is clearly a first approximation to Browns empirical formula. Consistency of this jet model with the detailed mathematical analyses of Powell and Cremer and Ising is exhibited. In particular, the necessity of parallel-drive is shown, and additional arguments to support it are advanced. Author
- Fluid Mechanics