  For accretion onto astrophysical black holes, we demonstrate that linear
perturbation of Bernoulli's constant defined for an inviscid irrotational
adiabatic flow of perfect ideal fluid gives rise to phenomena of analogue
gravity. The formulation of our work is done in the Newtonian framework and
also within the General relativistic framework, i.e., considering a static
spacetime background, as well. The resulting structure of the analogue acoustic
metric is similar to the acoustic metric found in perturbing velocity potential
and mass accretion rate.
