Future nanotechnology applications are likely to involve reactive or n
on-reactive species carried along a fluid stream. We have performed se
veral molecular dynamics simulations of a buckyball, C-60, cage or ide
alized atom in a helium fluid flowing axially inside a carbon nanotube
. The fluid was started at some initial velocity and both the fluid an
d buckyball allowed to recycle axially via minimum image boundary cond
itions. A buckyball introduced into the feedstream (started at zero ve
locity) usually reached fluid velocity within 5 ps. Leakage rates of h
elium past the C-60 depended on the nanotube diameter and fluid veloci
ty. These leakage rates and other important features of the dynamics c
hanged significantly when C-60 was modelled as an idealized atom or wh
en the nanotube was held rigid, suggesting that simulations of fluid d
ynamics inside nanomachines should be fully dynamic and atomistic.