Hydrodynamic properties of carbon nanotubes

We study water flowing past an array of single walled carbon nanotubes using nonequilibrium molecular dynamics simulations. For carbon nanotubes mounted with a tube spacing of $16.4\times 16.4\mathrm{nm}$ and diameters of 1.25 and 2.50 nm, respectively, we find drag coefficients in reasonable agreement with the macroscopic, Stokes-Oseen solution. The slip length is $-0.11\mathrm{nm}$ for the $1.25\mathrm{nm}$ carbon nanotube, and $0.49$ for the 2.50 nm tube for a flow speed of 50 m/s, respectively, and 0.28 nm for the 2.50 nm tube at 200 m/s. A slanted flow configuration with a stream- and spanwise velocity component of 100 ${\mathrm{ms}}^{-1}$ recovers the two-dimensional results, but exhibits a significant 88 nm slip along the axis of the tube. These results indicate that slip depends on the particular flow configuration.