Volume 109, Issue 1, January 2001
Index of content:
- NONLINEAR ACOUSTICS 
109(2001); http://dx.doi.org/10.1121/1.1328794View Description Hide Description
Godunov-type computation schemes are applied to numerical simulations of wave propagations in time-dependent heterogeneous media (solids and liquids). The parametric phase conjugation of a wide band ultrasound pulse is considered. The supercritical dynamics of the acoustic field is described for one-dimensional systems containing a parametrically active solid. The impulse response function, numerically calculated for a finite active zone in an infinite medium above the threshold of absolute parametric instability, is in a good agreement with the analytical asymptotic theory. The supercritical evolution of the acoustic field spatial distribution is studied in detail for parametric excitations in an active zone of a solid layer, loaded by a semi-infinite liquid on one side and free on the other.
109(2001); http://dx.doi.org/10.1121/1.1332383View Description Hide Description
It is demonstrated that the temperature oscillations near the edge of the thermoacoustic stack are highly anharmonic even in the case of harmonic acoustic oscillations in the thermoacoustic engines. In the optimum regime for the acoustically induced heat transfer, the amplitude of the second harmonic of the temperature oscillations is comparable to that of the fundamental frequency.