Richard Raspet
Jay A. Lightfoot
James R. Belcher
Henry E. Bass
Dept. of Phys. and Astron., Univ. of Mississippi, University, MS 38677
Thermoacoustic engines are placed in resonant cavities for Q amplification. Variations in the cross-sectional area of the resonator serve to reduce device volume and to minimize nonlinear distortion by detuning higher harmonics. In the case of a thermoacoustic sound source, these cross-sectional variations in the resonator area may be carried to an extreme such that the resonator approaches the Helmholtz limit. This limit produces a dimensionally compact, low-frequency thermoacoustic sound source. A thermoacoustic sound source in the Helmholtz limit has been constructed. The measured particle velocity and acoustic pressure in the device will be compared to Helmholtz idealization. [Work supported by ONR.]