Nontrivial influence of acoustic streaming on the efficiency of annular thermoacoustic prime movers

The nonlinear processes controlling the time-dependent evolution of sound in annular thermoacoustic prime movers are studied. It is demonstrated that, under some heating conditions, the evolution of the temperature field induced by the excitation of acoustic streaming provides an additional amplification of sound which results in a complicated periodic onset and damping of thermoacoustic instability. The study of this particular example provides the opportunity to demonstrate that the excitation of acoustic streaming does not necessarily imply a decrease in the engine's efficiency.