Numerical Simulation of Two-Dimensional Large-Amplitude Acoustic Oscillations

The two-dimensional nonlinear acoustic oscillations in the resonator of four different driving amplitudes are simulated by a gas-kinetic scheme. The shock in the resonator, the effects of the driving amplitude on the acoustic field and flow and the distribution of harmonics are investigated based on the simulaton results. Moreover, this work discusses the reasons for the nonlinear effects such as annular effect and velocity reverse. It is pointed out that the waveforms of the acoustics variables increasingly distort with the driving-amplitude increasing. And it is found that the acoustic field and the flow under the large-amplitude are quite different from those under the finite-amplitude. Moreover, it has been shown that the shock greatly affects the pressure, temperature and the axial velocity and has no effect on the radial velocity. All of this shows that the large-amplitude has a large effect on the nonlinearity in the resonator.