  This comment is on Phys.Rev.Lett. 144, 155302 (2015) by M.T. Reeves, T.P.
Billam, B.P. Anderson, and A.S. Bradley "Identifying a superfluid Reynolds
number via dynamical similarity" where a new superfluid Reynolds number is
introduced. This definition is shown to be useful in the data analysis of the
finite lifetime of turbulence observed with an oscillating sphere in superfluid
helium at mK temperatures in a small velocity interval $\Delta v =(v-v_c)$ just
above the critical velocity $v_c$. The very rapid increase of the lifetime with
increasing superfluid Reynolds number is compared with the "supertransient"
turbulence observed in classical pipe flow.
