THERMOACOUSTICS OF TRAVELING WAVES - THEORETICAL-ANALYSIS FOR AN INVISCID IDEAL-GAS

Standard thermoacoustic sources and refrigerators have the stack place d near one end in a standing wave tube. This selection of the stack po sition optimizes the thermoacoustic effect. For certain applications, however, the effect of a thermoacoustic stack on a traveling wave is o f primary interest. Equations governing wave propagation through a sta ck analogous to the short stack approximation of standing wave thermoa coustics have been derived for an ideal gas. When the wave propagates in the direction of increasing temperature, the wave is amplified by a n amount dependent upon the temperature gradient. Waves propagating in the opposite direction are attenuated. Counterpropagating waves in a standing wave tube encounter both. In this case, the results reduce to those developed earlier by Swift [J. Acoust. Soc. Am. 84, 1145-1180 ( 1988)] and others.