  A molecular dynamics (MD) simulation was performed to study the propagation
of soundwaves in a fluid. Soundwaves are generated by a sinusoidally
oscillating wall and annihilated by a locally applied Langevin thermostat near
the opposite wall. The waveform changes from sinusoidal to sawtooth with
increasing wave amplitude. For low-frequency sounds, the simulation results
show very good agreement with Burgers equation without any fitting parameters.
In contrast, for highfrequency sounds, significant deviations are obtained
because of acoustic streaming. The speed of sound can be directly determined
from the Fourier transform of a waveform with high accuracy. Although obtaining
the attenuation rate directly from the simulation results is difficult because
of the nonlinear effects of the wave amplitude, it can be estimated via Burgers
equation. The results demonstrate that MD simulations are a useful tool for the
quantitative analysis of soundwaves.
