  The symmetries of the general Euler equations of fluid dynamics with
polytropic exponent are determined using the Kaluza-Klein type framework of
Duval et $\it{al}$. In the standard polytropic case the recent results of
O'Raifeartaigh and Sreedhar are confirmed and generalized. Similar results are
proved for polytropic exponent $\gamma=-1$, which corresponds to the
dimensional reduction of $d$-branes. The relation between the duality
transformation used in describing supernova explosion and Cosmology is
explained.
