Investigation of Fluidic High Intensity Sound Generator
Final rept. 26 Feb 1968-24 Apr 1970
BENDIX RESEARCH LABS SOUTHFIELD MI
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The report summarizes the results of an investigation of a fluidic high-intensity sound generator concept. The investigation concerned the evaluation of a new type of proportional fluidic amplifier geometry, the annular slot amplifier. This amplifier was found to have significantly higher pressure gain than the conventional planar jet proportional amplifier, 4 to 12.5 versus 3 to 5. An annular slot amplifier model was tested over a frequency range from 300 Hz to over 2000 Hz. Its control port impedance was studied particularly. and the impedance as well as the amplifier gain were found to vary with frequency. The frequency dependence is attributed to a distributed-parameter feedback phenomenon in the vent region. An experimental two-stage sound generator was designed, fabricated, and tested. The second stage is an annular slot amplifier with its critical areas scaled up ten times over those of the first stage. The first stage control flow source is an electro-dynamic driver of the kind used with conventional loudspeakers. The second stage power jet area is 5.78 square inches, and the supply pressure is 10 psig. The radiating horn is exponential with a cutoff frequency of 180 Hz and an exit diameter of 42 inches.
- Fluidics and Fluerics