  Various properties of acoustic black holes constructed in Minkowski spacetime
have been widely studied in the past decades. Recently the acoustic black holes
in general spacetime were proposed . In this paper, we first investigate the
basic characteristics of `curved' acoustic black hole in Schwarzschild
spacetime, including the quasi-normal modes, grey-body factor and analogous
Hawking radiation. We find that the signal of quasi-normal mode is weaker than
that of Schwarzschild black hole. Moreover, as the tuning parameter increases,
both the positive real part and negative imaginal part of the quasi-normal
frequency approach to the horizonal axis, but they will not change sign. This
means that all the perturbations could die off and the system is stable under
those perturbations. Since the larger tuning parameter suppresses the effective
potential barrier, so it enhances the grey-body factor. The energy emission
rate of Hawking radiation does not monotonically increase of the tuning
parameter because of the non-monotonicity of the Hawking temperature. Finally,
as a first attempt, we study the acoustic black hole shadow. The radius of
acoustic shadow becomes larger as the tuning parameter increases, because both
the related acoustic horizon and the acoustic sphere become larger. Our studies
could help us to further understand the near horizon geometrical features of
the black hole. We also expect that our observations could be detected
experimentally in the near future.
