  We examine the effects of two-body interactions in a nuclear star cluster
surrounding a supermassive black hole. We evaluate the energy flux, analogously
to the particle flux calculation of Bahcall and Wolf (1976). We show that there
are two types of power-law steady-state solutions: one with zero energy flux
and constant particle flux and the other with constant energy flux and zero
particle flux. We therefore prove that a zero particle flux solution, which
corresponds to the case of an accreting supermassive black hole, can be
obtained by requiring a constant energy flux. Consequently, this solution can
be derived by simple dimensional analysis, bypassing the need for detailed
calculation. Finally, we show that this characteristic, of zero particle flux
for constant energy flux and vice versa, is not unique to the Keplerian
potential of a supermassive black hole but holds for any central potential of
the form $\phi\propto r^{-\beta}$.
