  We interpret measurements of the Reynolds number dependence of the torque in
Taylor-Couette flow by Lewis and Swinney [Phys. Rev. E 59, 5457 (1999)] and of
the pressure drop in pipe flow by Smits and Zagarola, [Phys. Fluids 10, 1045
(1998)] within the scaling theory of Grossmann and Lohse [J. Fluid Mech. 407,
27 (2000)], developed in the context of thermal convection. The main idea is to
split the energy dissipation into contributions from a boundary layer and the
turbulent bulk. This ansatz can account for the observed scaling in both cases
if it is assumed that the internal wind velocity $U_w$ introduced through the
rotational or pressure forcing is related to the the external (imposed)
velocity U, by $U_w/U \propto Re^\xi$ with xi = -0.051 and xi = -0.041 for the
Taylor-Couette (U inner cylinder velocity) and pipe flow (U mean flow velocity)
case, respectively. In contrast to the Rayleigh-Benard case the scaling
exponents cannot (yet) be derived from the dynamical equations.
